Dreamcast was the first target for Evil Twin's production. But In Utero used their middleware Phoenix3D to work simultaneously for the Playstation 2 & Windows PC version.
However, there are a few differences between them.
On Dreamcast, the game suffer from two missing levels and a higher texture compression. During ingame cinematics, voices acting cuts the soundtrack. Due to memory issue there is also less NPC. However lighting effects are quite good. Better than de PS2 version.
Whereas the game used to cost nothing in 2002/2003, it's now an expensive dreamcast game.
Playstation 2 & Windows
Windows & PS2 versions are almost the same. Even if the texture compression is less destructive on PC. The main difference are the lighting effects. There is almost nothing on PS2.