Game Boy Advance
The Game Boy Advance, often shortened to GBA, is a handheld video game system created by Nintendo and initially released in 2001. It played host to two versions of Doom:
Doom for Game Boy Advance was released by David A. Palmer Productions in 2001. This is a port of Doom based on the Atari Jaguar version. It is notably censored to obtain a "teen" rating from the ESRB, with most blood being changed to green.
Doom II for Game Boy Advance was released by Torus Games. This Doom II port is based on the Southpaw Engine, and differs in a number of fundamental gameplay aspects from any other version of the game.