This is a real decent version of Killer Instinct ported (from the SNES version) to the gameboy. The main differences are the sound, and graphics. The moves are still there, but some look like they are used differently. The combos are easier and fun on the GB version. I didn't really see blood in this one. Two characters (Riptor and Cinder) were not there. I have no idea why. Anyway if this is played on the GameBoy it was made for, then you can turn up and down the brightness, but this version has the smallest resolution. If you play it on the GBA, you will see extra color was added and you can now change the resolution with L to high, and R to low. Then if it is played on GBA SP, or DS, you will get better lighting of the screen obviously. This game is missing two characters and has few differences, but its worth to get it. Especially, if you want it for your Rare/Rareware collection, buy it! Many themes were also recongnized in this game. It feels like playing an original NES game on a GameBoy.