Here are some other oddities that I proudly have in my collection. You should check them all out, if possible.
GoGo Tank
Gremlins 2 - Actually a really good game, although quite short. The music on the last two levels is excellent.
Kung Fu Master - I don't know if this is a port or not, but it appears to be a bigger, better sequel to the game we know in the states as "Kung Fu."
Mario's Picross - Probably the best puzzle game on the GameBoy.
Mercenary Force - Terrible graphics and music, but strangely addictive gameplay.
Mole Mania - Awesome action/puzzler. Highly recommended.
Mystical Ninja - Yeah, it's on the GameBoy, too! And I have it! (never played it, though)
Nail 'N Scale - Hey, I got this one, too! (along with Battle Unit Zeoth, Cyraid and CosmoTank)
Ninja Boy - Don't know anything about this game other than the fact that I have it and the sequel is better.
Ninja Boy II - Don't know anything about this game other than the fact that I have it and it's better than the first one.
Snow Brothers - This one was hard to track down, and yet remains the least-elusive version of the game released in the US. Better than Bubble Bobble.
Spot: The Cool Adventure - Played McKids BITD? I did, and really liked it. For some reason, they turned the main character to Spot for the GameBoy version.
Stop That Roach - Another game I had to watch and watch and watch Ebay for. Plays nothing like Catrap, but I'd put it right there in the same league.
Tail Gator - Very cute and solid little platformer NOT made by Nintendo, which is oddly enough a rarity on the system.
TMNT: Fall of the Foot Clan - HAH! I love this game. The most-basic and
best of the 3 TMNT GameBoy games.
Who Framed Roger Rabbit? - There's a Sunsoft version and a Capcom version. I have them both. The dude behind this game later went on to create some scary game on the Playstation for Capcom. "Evil" something...