Actually, Dungeon Master for the Amiga, by FTL, is what all other 1st person shooter/adventures are based on. That includes DOOM. Dungeon Master invented the genre. Dune for the Amiga created the tactical strategy genre (Command & Conquor, Warcraft, etc.), SimCity started on the Amiga, so did Civilization and the entire "God" genre (Populous). Almost every good game genre was introduced because of the Amiga. PC's couldn't even play decent games until the early 90's for gosh sake. :-D
I do recall a couple ram "hacks" for the 500, but mostly I remember that you had to modify a couple different pins (pin 41 on the Fatter Agnus 8372A and pin 32 on Gary) if you were doing them to non NTSC units. I also seem to recall that all internal RAM hacks just gave you more CHIP RAM (up to 1MB, I do not recall a 2MB hack but it might have been possible with a Fatter Agnus 8375), and I also recall that this hack also disabled any RAM expansion you intended to later add in the belly expansion bay, although the clock on a 501 would still function the additional 512k of fast ram wasn't seen. You could still add FAST RAM on the external Zorro slot using a SupraRAM or similar expansion device however.
My memory isn't the best when it comes to internal 500 hacks, but I do recall having soldered ram both onto the motherboard and "piggyback" onto the existing motherboard ram. But for some reason I seem to remember having 2MB CHIP RAM on a modified 2000/2500 but never on a 500. I could possibly be mistaken -- although because of the availability of the 8375 Fatter Agnus, [318069-17] was only for the 2000 with other 8375 versions only being available for the 3000 and 600, I doubt it was possible on the 500.
