Doom wasn't an original game for Amiga, there are ports of the PC Game such as ADoom and DoomAttack, you can download them from Aminet and you need the WAD file from the original PC version of Doom, Doom 2 or Final Doom
They need at least an 020 + Fast Ram to run, you wont have much fun without an 030+ 8mb and that is pretty slow, you'll have a nice experience with 040+
Steve.