It's neither Doom nor NetHack; it's quality Amiga emulation that proves the maturity of any platform, and Android owners will be happy to know that their smartphones can now brilliantly emulate the best 16-bit computer ever. This of course means they can also play the tons of classic Commodore Amiga games released through the ages, including such unsurpassed gems as Sensible Soccer, Agony, Monkey Island, Alien Breed, Space Quest III, Xenon II, Kick Off 2, Shadow of the Beast, Lemmings, Ishar, Another World and -oh, well- I can go on for ages. Anyway. The emulator you're looking for is UAE4Droid and you can, among other places, grab it here. Oh, and I do suggest you have a look at this very handy guide of getting things to run smoothly.