My guesses:

Super Frog Vs. Earthworm Jim
Septerra Core Vs. Anachronox
Blake Stone Vs. Rise of the Triad
Duke Nukem 3D Vs. Redneck Rampage
Planescape Torment Vs. Baldur's Gate
Fallout Vs. Arcanum
Deus Ex Vs. Thief
Broken Sword Vs. Gabriel Knight
The Longest Journey Vs. Syberia
Gabriel Knight 2 Vs. Phantasmagoria
Theme Hospital Vs. Rollercoaster Tycoon
Serious Sam Vs. Painkiller
Psychonauts Vs. Beyond Good and Evil
Waxworks Vs. Realms of the Haunting
Master of Orion Vs. Alpha Centauri
Oddworld Vs. Another World

This would put me in serious trouble. Alpha Centauri is much deeper (from what I played in the few last weeks) but Master of Orion 1 &2, I loved every minute playing them years ago, too.

Journey to the Center of the Earth vs VR Soccer vs Big Rigs: Over the Road Racing?

I kid, I kid.