Some personal achievements and memories...
First successful landing on the air craft carrier in F/A-18 Interceptor. Took some patience, and trepidation. And achieving a 1:1 ratio for missiles fired to bogies downed. Subsequent simulations I tried (F-29 Retaliator and Thunderhawk AH-73M) had cheats/trainers enabled, so didn't provide the same challenge.
Being awed by Shadow of the Beast 2 intro. Then many hours later realising how I wouldn't be completing the game without a cheat, and having to wait for the next publication of Amiga Format for the liberating "ten pints" cheats.
Completing Eye of the Beholder and enjoying a proper ending. No after-thought single screen of congratulatory text here. Still need to complete the game again to this day, now that I know all the "Special Quests". To see if there's an additional ending reward.