This is a less exciting screenshot but I added a mode for people with low power pcs, which completely turns off all lighting.

With the framerate limiter completely off I can get over 700 fps in this mode.
I don't recommend that though as the games physics start freaking out after the engine gets past 500 fps.
Edit: added some subtle shading to the walls in this mode to make it look a bit better.

But yeah, things should be good for most people now.
Now I just need to make a better options menu to contain all the new options. Which is not very fun :(