Well, I'd have to say my ultimate favorite, has to be
TurboRaketti II. Obscure shareware two-player duel with Asteroids' style control and multiple weapons, in a big scrolling maze of obstacles. I don't know what it is, but when you learn to pilot those little triangles among the rocks at top speed, deliver a bomb to your enemy, and escape, you're addicted

Look for it online. PAL only, I think. (TurbokRaketti I and GravAttack are interesting and similar, but just not the same.)
Runner-up: the original
Lemmings in 2-player mode with 2 mice. An Amiga-only adventure in pure aggravation. I challenge any friendship to withstand a night of 2-mouse Lemmings.
I also enjoyed StarGlider 2 (the original "Descent"?), MindWalker, Shadow of the Beast, It Came From the Desert, Obliterator, Stunt Car Racer, and Sinbad.
And there's a ellipse-shaped PAL shareware game I really liked--great graphical style, shooting in from the rim towards little blobs that grew and grew. I think it was called Microbe or something similar.
And for some odd reason, I really liked New Stubb City, made with VR Construction Kit. I guess I was a sucker for any kind of 3D.
Special mention must be made of Space Spuds. My X-Specs 3D still work

I do remember Sensible Soccer, though--the only sports game I've ever gotten into I think!