There's also Arx Libertatis for Arx Fatalis. Arkane (yes, that Arkane) released the source code for the game. This is a new engine and patch that is basically required. Even if you could play the game on a modern computer (you can't really) you wouldn't want to play without this patch. It does things like making drawing the runes for casting spells more reliable. (For those not aware, you drew runes on your screen and combined them to create spells. You didn't just press a fireball button. You had to figure out what spells combined to make a fireball, and then draw it.)

If you like ImSims or Arkane games, I highly recommend Arx Fatalis. No one has done magic like it since. To be fair, it was one of the slowest and most cumbersome ways to do magic, but it did actually feel like you were part of it. You could cast spells before you learned them if you had the rune and guessed the combination (they all make sense). There were even some spells never told in game that you were expected to figure out. Cheats were even activated using the system, by drawing a certain combination of runes. It's all very cool, and I wish we would get a second modern version of the idea.