Faceball 2000 ROM

Also, be sure to check out Buster Bros.

Faceball 2000, also known as MIDI Maze, is a networked first-person shooter maze game for the Game Boy developed by Xanth Software F/X and released in 1991. The game takes place in a maze of untextured walls. The world animates smoothly as the player turns, much like the earlier Wayout, instead of only permitting 90 degree changes of direction. 

Faceball 2000 is a first-person shooter. You control a H.A.P.P.Y.F.A.C.E., or Holographically Assisted Physical Pattern Yielded For Active Computerized Embarkation. The graphics consist of flat shaded corridors. Enemies are all simple geometric shapes with smiley faces on them.

Although the graphics are simple, they allow for full freedom of movement, not unlike Wolfenstein 3-D. There are two modes of play. First there is a single player mode in which your goal is to find the exit to each level. There are 70 mazes in this mode. The second mode is the multiplayer arena. For the Game Boy: up to 4 Game Boys can be linked together in this mode.