Tyne has updated his Quake Mod for the Dreamcast, heres whats new:

Attempted to fix Dreamcast support, untested
- Vigil can now run along walls!
- Updated readme.txt
- Castle2.bsp is included, however far from finished as you'll see .. simply knock down that door at the end of castle and you'll go into it!
- A few new special effects, mostly looks good with transparency
- New sprite explosion for the Flaming Head Smash attack
- New music for Castle 2 (temporary?)
- Vigil's animations have been tweaked
- A few bug squashed
- New dynamic camera that works on Dreamcast and low level engines even!
- New animation for Vigil! for example, when Vigil dies he now does a forward flip to get up and looks pretty cool
- Fire Beam has increased twice in size and is more effective
- Vigil has a new attack, an auto aiming diving swallow performed while wall running, he can also do a wall run spinning jump!
- Ledge grabbing is overall improved
- Vigil can now double jump after a wall jump, meaning he can climb verticle tunnels very fast and gain more overall height

As you can see, the list of changes is growing smaller compared to older versions! The reason for that is, it's almost gold in terms of gameplay!
I just need to add bosses, way more monsters, levels, and a cutscene for the ending and whatever else I can think of.

Download at link above.