Jurassic Park Rampage Edition, getting its earliest prototypes to work

[GelmiR]

Back in 2008, DRX dumped a large number roms, including a number of prototypes for Jurassic Park Rampage Edition. The earliest 2 roms are dated June 20th and June 22nd, 1994. To the best of my knowledge, they have never worked on any emulator. I have asked Tony H. if there was a way he could get them to work with Game Genie codes. So far, he has gotten the June 22nd version to boot and we're now able to start up the Cargo Ship level. We decided to split this from the Game Genie codes topic into its own. Most of the information we have so far and a screenshot found below:

Been looking at them for awhile, and there are two things that I've figured out about the June 22nd prototype ...

It doesn't look like there is any kind of checksum check, so that's not the problem.

I compared an assembly trace log from the June 22nd ROM to the June 30th ROM on startup. Without going into boring details, it looks like either some of the programing at the very end of the ROM is corrupted, or someone intentionally changed some bytes so the game wouldn't boot. The game/programming actually goes into the header of the game as if it was programming (which it isn't). The header contains things like the name of the game, region, etc. I tried several different things to force it to boot, but failed.

Good news, I got the second prototype (June 22) to boot as far as the SEGA screen. Making progress. Interestingly, there is no dinosaur walking past like in the June 30th proto.


Update: Got the prototype (June 22) to boot up to the title screen.

GelmiR, since there are so many Game Genie codes needed to get this Jurassic Park Rampage Edition June 22nd prototype running (21 codes so far), I'm just going to email you the patched ROM. There are a few things you'll need to note:

1) I've only tested it with Gens, so don't know if it will work with other emulators.
2) The game will only load once. If the game freezes, you can't just "reset" the emulator. You'll need to exit the emulator, restart it and reload the ROM.
3) When you get to the Start/Option screen, you'll only have a few seconds to select "Start", or else the game will freeze (will take a code or two to fix that). You can also select the Option menu if you'd like.
4) When you get to the map screen, make sure you select Cargo Ship. Although I haven't tried the other levels very much, I don't think they work (will need more codes to fix them).
5) When Cargo Ship starts, you can shoot your default weapon in either direction, jump, walk left or right, or change your weapons. The game will freeze if you try to shoot other weapons (will need more codes). Also, if you walk far enough to the right the game will freeze when you encounter enemies.
6) There is no sound. Could be because there is no sound in this proto, or because of what I had to do to get the game running.

There's a good chance that you'll be only the second person to ever see this prototype working (besides the developers). You'll find that there are a lot of differences in this ROM that aren't in any of the other ROMs. I think you'll have a field day with this prototype.

I'll keep you updated when I make significant progress on the ROM.

Wow, this is awesome, thanks so much for your efforts so far!

And I might be one of the few who will ever see this, but I do know of a few other people that would love to see this and know about this. Edit: I misread, I thought you meant I'd be one of the only persons who'd ever see this, but you said that I was probably only the 2nd person to see it That's probably very true! I probably read too fast due to enthusiam. Is it okay if I pass this on to Glitch as well? He's the one that posted who posted at the SonicRetro.org forums. He also posted at TresCom, sorry about not being able to read that topic, I didn't think signing up was neccessary. I think regarding the non-working protos, his post at SonicRetro was more useful, but I will send you the text by mail anyway just to be sure. The main reason why I ask if I can pass the patched rom on to him, is that he will probably want to make a YouTube video for it. He has done so for the other prototypes as well. You can find his channel here: https://www.youtube.com/user/glitchhunter09/
I'll ask if he's interested in coming over, this might be something that needs its own topic?

I am currently running your patched rom with Genesis Plus GX on my Wii. So far I have encountered the same things you mentioned, though I can use the Reset function without any problems. Other things I have noticed:
- Grant's default weapon is a pistol/revolver instead of a dart gun
- The ammo/health colors of the HUD are in red instead of green
- There's what appears to be a grenade icon above the weapon icon

Edit: When Cargo ship is selected, you can press C to change it into Hidden Ruins (don't think I've ever seen its icon as it only shows the names of the final levels on the map, not the icons), and A to change it back to Cargo ship. Hidden Ruins doesn't load either, though.

Edit 2: All screenshots I take in this emulator have a 320 x 224 screen resolution. The screens for this proto come out as 320 x 240. I don't know a thing about screen resolutions for Sega Genesis, but I noticed the difference and thought I'd point it out just in case.

That's all for now, very interesting stuff - thanks again!

GelmiR, by all means, send that patched ROM to whoever you want. The more the merrier. Just make sure they know that they'll need to select Cargo Ship, and the rest of the notes I mentioned above. Also, keep in mind that I'll be making more improvements to that ROM in the near future. I even have an idea on how to fix the entire game with a single code. Will be looking into that today.

I agree, this should get it's own topic. Would "Genesis Does" be the best place for it?

EDIT: If you want to start the topic, please do so.

[Sik]

I compared an assembly trace log from the June 22nd ROM to the June 30th ROM on startup. Without going into boring details, it looks like either some of the programing at the very end of the ROM is corrupted, or someone intentionally changed some bytes so the game wouldn't boot. The game/programming actually goes into the header of the game as if it was programming (which it isn't). The header contains things like the name of the game, region, etc. I tried several different things to force it to boot, but failed.

*ding!*

Looks like those builds need the devkit to boot as-is (・～・) The way the debugger works is first the ROM is loaded then it overwrites some 68000 vectors to point to itself, and the debugging code would be added at the end of the game (no idea how that worked with 4MB games tho, but it's how it works for smaller games at least). So they don't boot because part of them is missing, technically.

In other words, yeah, gotta fake the debugger's boot sequence (which seems to be what has been hacked in to get them to run, at least?)

[Tony H]

More good news, I've made some major improvements using far fewer Game Genie codes (from 21 codes down to 6). Everything seems to work now except the sound. All the levels work, can select characters now, and the game resets correctly in the emulator. Will do some more testing and keep you posted.

EDIT: All the weapons work now too.

[Tony H]

GelmiR, Just emailed you the latest fixed ROM. I'm going to go out on a limb and say that the game appears to be 100% functional now, with the exception of the sound. Let me know if you find any problems and I'll take care of them.

[Tony H]

*ding!*

Looks like those builds need the devkit to boot as-is (・～・) The way the debugger works is first the ROM is loaded then it overwrites some 68000 vectors to point to itself, and the debugging code would be added at the end of the game (no idea how that worked with 4MB games tho, but it's how it works for smaller games at least). So they don't boot because part of them is missing, technically.

In other words, yeah, gotta fake the debugger's boot sequence (which seems to be what has been hacked in to get them to run, at least?)

Thanks for the info. Will look into that.

[GelmiR]

Nice to see someone finally got this thing kinda working. I was a little worried the ROMs were corrupted beyond use. I had some Sonic community hackers look at it in a hex editor once. They said there were a lot of FF's in places which might be some of the problem. Also, I've read the programmer's resume and he revealed in it that He build Rampage Edition off of the original Genesis/Mega Drive game in his spare time. It's been a while since I read his resume:

https://web.archive.org/web/20060412...80/resume.html

"Jurassic Park was a 1.3 Million unit selling game and was completed on an extremely short schedule. JP: Rampage Edition had a similar schedule, with fewer engineers, but the redesigned game engine enabled it to be finished on time with a higher degree of quality."

There's other stuff there too. Sorry if I got off topic. Moderators can move this to the thread my pal made if they wish.

Quoted you from the Game Genie codes topic, so this won't get buried in the forums Rampage Edition has been one of my favorite Mega Drive games for as long as I can remember. Very interesting stuff, thanks for sharing!

GelmiR, Just emailed you the latest fixed ROM. I'm going to go out on a limb and say that the game appears to be 100% functional now, with the exception of the sound. Let me know if you find any problems and I'll take care of them.

Sweeet, thanks! Gonna boot it up right now and play through, will let you know of any problems I have!

[BigEvilCorporation]

Thanks for the info. Will look into that.

Here's the SNASM2 version of that code, other debuggers (PsyQ, SProbe, VAX, etc) will be similar:

   ; Setup traps/exceptions to allow SCSI debugger access
MSCSITrap   equ 0x108008
MSCSIExcept equ 0x10800C
 
DBG_ConnectDebugger:
 
   move.b d0, 0x108000 ; Allow write to SNASM RAM
   move.l #0x02<<24+MSCSIExcept, 8+(4*0)
   move.l #0x03<<24+MSCSIExcept, 8+(4*1)
   move.l #0x04<<24+MSCSIExcept, 8+(4*2)
   move.l #0x05<<24+MSCSIExcept, 8+(4*3)
   move.l #0x06<<24+MSCSIExcept, 8+(4*4)
   move.l #0x07<<24+MSCSIExcept, 8+(4*5)
   move.l #0x08<<24+MSCSIExcept, 8+(4*6)
   move.l #0x09<<24+MSCSIExcept, 8+(4*7)
   move.l #MSCSITrap, 0x80
   move.b d0, 0x10F001 ; Write protect SNASM RAM
   ori #0x8000, sr     ; Enable TRACE exception
 
   rts

[GelmiR]

Okay, so I did a quick test for the ROM Here are the issues I encountered:
- Game freezes when pressing Pause
- Game freezes when leaving the screen, this happens in the Savannah level when walking off-screen left or at the right, at the end of the level
- Game froze on my once in the Aviary level, couldn't repeat it

Normally as Grant, when you start, you can choose from the Cargo Ship, Aviary, and Savannah levels. For the last levels, the game takes a more linear approach and lets you play the Hidden Ruins, River Run (aka Raptor Rapids) and the final level, Burning River. I have been able to play:
- Aviary
- Cargo Ship
- Savannah
- Hidden Ruins

I have been able to start the River Run level. Grant starts just above the river boat, as you move, you will fall down and land in the boat. The game will freeze a second later, though. So this level is not yet playable. As in the later builds, none of the levels have their exits working. I could access Hidden Ruins and River Run by using the X, Y, or Z buttons. I'm not entirely sure which I pressed, as I'm using a Wii Classic controller and it's been ages since I configured it.

As the Raptor, the game is not really playable. When you try to run, the Raptor glitches/dies. But this also happens in the June, 30th build.

Was really cool to take a look at this, thanks again! Hope River Run (and subsequently, Burning River) can be fixed There might be a way to access that with X/Y/Z, too, but I haven't had any success yet.

[Tony H]

GelmiR, just emailed you the newest revision. I was able to fix the pause problem, and the problem in the River Run level where it freezes at the very beginning right after he drops into the boat.

There is still a problem in the River Run level a little further down stream. The boat seems to get stuck in some logs or something, and then the game freezes. You might be able to work around this problem by not getting stuck, but not sure. This might be a bug in the prototype because the assembly trace log didn't show the usual problem like with all the other problems that have been fixed.

The problem with the Savannah level where the game freezes when going off screen to the left or all the way to the right, might also be a bug in the prototype. Again, wasn't able to see the usual problem in the assembly trace log. Since the far right end of the level seems to be the exit, maybe this is the problem you mentioned where none of the exits are working.

I was able to get to the upper levels in the level select screen by pressing X for Hidden Ruins, and Y for River Run.

Not sure how to get to the final level (Burning River). If we need to play through one of the levels to get to it, I'm sure I can make a level select Game Genie code so we can play that level as well.

I'll explain shortly why this prototype didn't work in the first place, and what I did to fix it.

Let me know if you find any more problems in this latest ROM. I'll post the Game Genie codes as soon as we're pretty sure that we've got everything covered.


EDIT: Figured out how to get to Burning River. On the level select screen, just press Z. The Burning River icon appears to be out of sight, so you'll know you have it selected when none of the levels are showing. Looks like a fun level. I keep getting eaten by that damn dinosaur. lol.

[GelmiR]

GelmiR, just emailed you the newest revision. I was able to fix the pause problem, and the problem in the River Run level where it freezes at the very beginning right after he drops into the boat.

There is still a problem in the River Run level a little further down stream. The boat seems to get stuck in some logs or something, and then the game freezes. You might be able to work around this problem by not getting stuck, but not sure. This might be a bug in the prototype because the assembly trace log didn't show the usual problem like with all the other problems that have been fixed.

Tested pause on all levels with both Grant and the raptor, I can confirm the fix works I have the some problem with the River Run level. Normally, you can just pass those tree root things. I'm not sure how to describe what happens, but it sounds as the same thing you ran into. It's part of the background, though - so that's probably not the cause?

The problem with the Savannah level where the game freezes when going off screen to the left or all the way to the right, might also be a bug in the prototype. Again, wasn't able to see the usual problem in the assembly trace log. Since the far right end of the level seems to be the exit, maybe this is the problem you mentioned where none of the exits are working.

It's not a big deal, but I thought you should know about it freezing there, just in case. They added invisible barriers in later builds. Actually, in the final, the level ends just (very) slightly before reaching the very end. I did find sort of a working exit, it's at the end of the Hidden Ruins level. The screen goes black, and the restarts the level.

I was able to get to the upper levels in the level select screen by pressing X for Hidden Ruins, and Y for River Run.

Not sure how to get to the final level (Burning River). If we need to play through one of the levels to get to it, I'm sure I can make a level select Game Genie code so we can play that level as well.

I wonder if the "level select" by using X/Y/Z still exists in the final? Also, on the map screen, you can change between Grant and the Raptor by pressing A or C.

I'll explain shortly why this prototype didn't work in the first place, and what I did to fix it.

Let me know if you find any more problems in this latest ROM. I'll post the Game Genie codes as soon as we're pretty sure that we've got everything covered.

Great, I look forward to it! I did find out that the game is playable as the Raptor after all. There are two ways to run; press left or right and up, or press left or right twice. The latter seems to work, but pressing up at any time is insta-glitch-death. So it seems I have some more testing to do as the Raptor But as Grant, other than the River Run level, I've had no more problems!

EDIT: Figured out how to get to Burning River. On the level select screen, just press Z. The Burning River icon appears to be out of sight, so you'll know you have it selected when none of the levels are showing. Looks like a fun level. I keep getting eaten by that damn dinosaur. lol.

Nice! This will make testing a lot easier. I could also leave the screen to the left without the game freezing. Rexy is a LOT faster here than in the final. I escaped her to the end of the level, but there is no exit present. I left the screen to the right, until I saw the coordinates would stop updating. That's when she still got me, LOL.

Edit: I should have been more clear about River Run and Burning River, sorry about that. You see, Burning River HAS no icon. It's (only for Grant) a continuation/extention to River Run. Once you complete River Run, you will not be taken back to the map, but continue the game instantly with Burning River.

[Bramsworth]

There's also a build of Wacky Worlds from that whole release which only loads one screen that looks radically different from the final. Just frozen there though. I've always assumed you can get the game to go further but something's preventing you from being able to enter any levels. Would be neat if someone looked into that.

[GelmiR]

Did a testrun of all levels with the Raptor. They all work, except for the Aviary. That level loads, but when trying to go upward in the level, it freezes. I found that by using the left stick of my Wii classic controller, I enabled a map mode. That means you can probably use a second controller to enable this - I seem to recall Glitch mentioning this. It was something similar to what could be used in the first game. I was able to use the map mode to skip that specific height point in the Aviary, level seemed to work fine from there. But when traveling down back to that height, it freezes again.
For Grant, this map mode seems more like a mix between map mode and no clip. Not sure how to describe it, I'll need to do some more testing.
Edit 2: In Aviary with the Raptor, you have to climb all the way up, move right, and from there, travel down. So it freezes at the start, but it will also freeze on the other side of the level when reaching the same height.

Edit: Leaving the screen as the Raptor hasn't frozen the game for me. But the coordinates do indicate that you sort of "fall off the world" at some locations when doing so :P

[Tony H]

The problem with the Raptor in Aviary doesn't appear to be caused by the corrupted part of the ROM, so no easy fix on that one.

I think we've gone about as far as we can go, so I'll post the Game Genie codes that get the ROM up and running. A few notes:

These Game Genie codes will work fine with Kega Fusion. When you start the game in Fusion, you'll of course just get a blank screen. Enter and enable the Game Genie codes and then restart the game by clicking on Hard Reset.

These codes will probably not work with Gens. When the game first loads (before you have a chance to enable the codes), the game locks up. Even after you enable the codes, doing a hard reset won't start the game. There is a way around this though. Hack the Game Genie codes into the ROM with a hex editor and the game will work fine in Gens (or most other emulators). GelmiR said that the hacked ROM works fine using Genesis Plus GX on the Wii.

Let me know if there are any problems not mentioned above.

Jurassic Park Rampage Edition (Prototype June 22) (Genesis) Game Genie codes

RZMB-86WC +
RZMB-86YA +
RZNV-86Z0 +
RZNB-86W2 +
RZMV-8618 +
RZNB-86WL +
RZNB-86V6 +
RZNB-86T6
Makes the game playable. This prototype was previously unplayable because of what appears to be a corrupted section in the ROM. All the levels work, although there are 2 exceptions. The River Run level will freeze when using Grant at some point. The Aviary level will freeze when using the Raptor when you get to a certain height. Also, there is no sound.

===============

Here's an explanation on why the game wouldn't run, and what I did to fix it.

There appears to be a chunk of the ROM in the $1F5642 to $1F59DF area that is corrupted. I don't know the total area that is bad, but that range listed appears to bad.

There are several times during game play that the programming in the game will try to jump to the bad section of the ROM. What I did to fix the game was to insert an instruction any place in this corrupted area so that when the programming tries to jump there, the instruction I inserted simply tells it to return to where it came from and continue on. There are 8 places where I inserted this "return" instruction, and the game tries to access those 8 places many times during game play. Since that part of the ROM is corrupted, it's very difficult to tell what it's supposed to be doing. It's possible that it has something to do with sound, which would explain why the sound doesn't work, but it's also possible that the sound didn't work in this prototype to begin with.

Here is what it looks like at the assembly level when the game tries to jump to the bad part of the ROM...

00:83FA 4E B9 JSR ($001F583C) = Here, the game is going to jump (JSR) to ROM address $001F583C (which is part of the ROM that is corrupted).

1F:583C FE BA Bad Opcode = It has now jumped to ROM address $001F583C, but since this area is corrupted, it doesn't recognize the opcode (which is why it's saying "Bad Opcode).

00:0000 00 00 ORI.B #$00,D0 = Since it just encountered a bad opcode, it sends the game to ROM address $000000. This address (and this part of the ROM) doesn't contain any opcodes and the game will eventually lockup/freeze.

There are several Genesis games that have built-in error handling routines that whenever it encounters a bad opcode (or other problems), it will automatically run a error handling program so the programmers can figure out what the problem is. I'm not very familiar with error handling routines, but I'm guessing that if there is no error handling routine, it's possible that the default address that it goes to is $000000. Again, that's just a guess.

Sik had mentioned that it's possible that this prototype needs a Devkit to run correctly. I'm not very familiar with Devkit kits, so can't really say if that's the case here.

Anyways, hope everyone enjoys this prototype.

EDIT: If I can figure out how to change the address that the game goes to if it encounters a bad opcode, I can potentially shorten the number of Game Genie codes needed to fix this game down to one or two codes. Will investigate.

[Sik]

These Game Genie codes will work fine with Kega Fusion. When you start the game in Fusion, you'll of course just get a blank screen. Enter and enable the Game Genie codes and then restart the game by clicking on Hard Reset.

These codes will probably not work with Gens. When the game first loads (before you have a chance to enable the codes), the game locks up. Even after you enable the codes, doing a hard reset won't start the game. There is a way around this though. Hack the Game Genie codes into the ROM with a hex editor and the game will work fine in Gens (or most other emulators). GelmiR said that the hacked ROM works fine using Genesis Plus GX on the Wii.

Gens needs byteswapped codes ._.

[Tony H]

I found the part of the ROM (in the header) that determines where to send the game in the event of a bad opcode. As I had guessed, it is set to $000000 by default. I tried changing it so that it would send the game to a "return" opcode (RTS). It worked, but instead of going back to where I thought it would, it sent it to somewhere else that wasn't a valid ROM address. Will do some more checking.