Dragons Lair - Until I stopped watching someone else play it and had a go myself.
Silkworm - I'd seen Amiga screenshots in Zzap before but I'd never heard Amiga sound and the sound FX in this game (especially the smart bomb boooom) sounded fantasic coming from a good stereo.
Elfmania - Finally someone wrote a fighing game that didn't seem to play in slow motion (and the graphics were very polished too), and it didn't require AGA
Turrican II - Mainly for the intro music, but also a technically impressive game.
Lotus Esprit Turbo Challenge - After plenty of slow and unconvincing racing games (turbo outrun / chace HQ 1 & 2) finally someone did it right - the same guy that did trailblazer on the C64 too
Fast and smooth.