A bunch of new WADs are available for Doom for the PSP, courtesy of michalt441. There are four mods available: Duke Nukem, Quake 4 and Quake 2, and Fistful of Dollars (based on the movie of the same name, starring Clint Eastwood).
Michalt441
has personally tested all these games and remarks that they work,
although some of them crash sometimes. Michalt441 promises to release a
compilation of even more WADs for Doom in the future so you can watch
out for that one.
Here are some notes before you get all gung-ho. The
Quake 4 mod only has one level available, while the
Quake 2 mod replaces 10 entire levels for the game. Ok, there, go gung-ho.
Remember, these are known to crash units so be careful when using them.
Download:
Doom PSP mod - Duke Nukem
Download:
Doom PSP mod - Quake 2
Download:
Doom PSP mod - Quake 4
Download:
Doom PSP mod - Fistful of Dollars
