The items in the GB game, which can raise your monsters' health, lower your opponents' health, and rig coin flips, among other things.
Stalling is an incredibly easy and effective way to get through the GB game: if you have more GUTS than your opponent, you can line up your entire hand with defense cards, and wait until the opponent attacks to use them. This way, the opponent will be forced to waste their GUTS just to wear down your defense, while you get to build your own GUTS for powerful abilities. There are attacks that circumvent blocking and dodging, but the former are weak while the latter are expensive.
Some attack animations, and Colt being sucked into the plate at the beginning.
Some "Event!" cards cause scary music to play. Even worse if it's on the last few turns, where it speeds up.
The GB game has invisible enemies that move very fast, drawing you into battles if they catch you.
Surprisingly Improved Sequel: The first game was released for the Game Boy, the second one for the PlayStation. Besides graphics and music, the game in general is smoother, and has a decent translation. It also has more monsters than the Game Boy version.
Tier-Induced Scrappy: Gali is low-tier in the Game Boy game, as his techniques are much more costly than any other Monster's, even his dodging cards. He has more uses in the Playstation version, though he's still a costly Monster to use.