Unsung, a World War I adventure in Wolfenstein 3D, lets you slog through the trenches in true pixelated FPS fashion.
Here is a little demonstration of the Unsung running on the Dreamcast. In general it looks just the same as on the PC, though Unsung runs at a faster frame rate on the PC than on the Dreamcast.
Uh... How is this possible?
I wish I could play Wolf 3d on my PS2 :)
Dreamcast is an open system much like the PC is, and it has the oldest homebrew community still active on the net.
Get a Dreamcast, so you can play Half-Life mods Paranoia and They Hunger on it!
Moddb.com
Moddb.com
Paranoia pushes the Dreamcast to its limits, and many people say this mod is on par graphically with Half-Life 2 source engine mods.