Well, I remember when I saw Another World's intro, and how the game played so much like an epic, unfolding tale, with gameplay seamlessly interspersed with cinematics, my jaw really did literally drop. As it did when I first began immersed in the vivid atmosphere and absurdly addictive gameply of Speedball 2, one of the few sport games that I liked on the Amiga.
Also, when I first saw the gorgeous graphics of Body Blows Galactic, I fell in love, and I still like the game, even though its fighting mechanic are far from perfect. My jaw more recently dropped when I finally got to play Shadow Fighter, a truely great Amiga Beat em up.
Getting back to the 3d graphics, I was totally blown away by the gameworld presented to you in Interphase. What an awesome game, and such a novel idea! So weird, so surreal, so cyberpunk...excellent! The game world, and the spooky, nostalgic storyline you find yourself in It Came From the Desert also had me hooked for ages, even though I never got far in the game. I still suck so hard at adventure games.
But come on...if there was one game to take your breath away, in all respects...it was Gods!!! From the gorgeous artwork, to the enchanting sound effects (the "thud thud" of Hercules boots, and his various groans when he jumps and is wounded my personal favourites), to the challenging, yet not impossible game structure, intricate puzzles, and a computer AI which reacts to how well, or how poorly, you are playing, nothing else comes close.