1) Needs no explanation, other than "FROG BLAST THE VENT CORE!"
2) Tetris. Greatest game ever. Period.
3) Sonic the Hedgehog. One of the first games I ever played. I like the whole series, but Sonic the Hedgehog was, and still is, my favorite.
4) Star Ocean II. By far the best RPG that I have played. I have found that the battle system holds up a lot better than those in Squares games, and every time I play through, I learn something new.
Those are the four games that I played the most as a child. I also really enjoyed the Ecco series for the Genesis, and Ambrosia's earlier games, including the original Escape Velocity (can you tell that I have been a Mac person for a very long time?). More recently, I have had a lot of fun with the Metal Gear Solid series, Castlevania: Symphony of the Night, and several of the early Square RPGs (FF and Crono Trigger, specifically). I didn't have a Nintendo as a kid, so I didn't get to play those until I was in college, and learned about emulators.
In the last couple of years, I found Rez and Shadow of the Colossus. Both are works of art, but for different reasons. Rez is perhaps the only game that I have enjoyed that focuses on music. Most of the music based game seem to be about mashing buttons in time to the music, which doesn't really suit me. Rez, on the other hand, has visuals and gameplay that go with the music, but do not depend entirely upon it. Shadow of the Colossus, on the other hand, is just stunning. The visuals are amazing, and the sense of isolation and loneliness are incredibly well done.
Finally, Darwinia. That is perhaps my favorite game. You should all play it.
xander
