You know, I really can't remember. Fantasy World Dizzy sticks in my head certainly as being
one of the first games I finished... Hmm. I'll go with that for now, unless I have a flash of inspiration.
EDIT: Oh actually, I know! I'm pretty sure it was 1994: 10 Years After on the Spectrum. Man, that was good! Well, for the time...
I wonder if it can stand the test of time? Time to load a Speccy Emulator, methinks!
Oh, and the original Prince of Persia was an early one, too. Not the first, but a huge accomplishment for me nonetheless. The 60-minute time limit was a real beeyatch.