(CW: suicide) Continuing on the topic of weird games I played online as a preteen, I also found Suicide Guy on Flashpoint, a (demo of a) first-person Unity game where the goal is to take your own life in various ways. It was exactly as short and creepy as I remembered! I'm pretty sure even at the time I thought it was a bit of a messed up premise for a game, but I was morbidly curious, so. I can't complain about the controls too much, but the bobbing of the character's head is just, blegh.
And I played two LEGO games, Supersonic RC and Junkbot. These were Shockwave games. The former is a third-person 3D driving game where you're a little LEGO remote-controlled car driving around a toy store. It was nostalgic, but the music was annoying, and the controls were, wouldn't you know, a little clunky. Junkbot is on the other hand rightfully considered to be one of the greatest Shockwave games period, it's a puzzle game with a simple premise and it's done pretty well.