Invulnerability colormap bug

When the player becomes invulnerable, his visual perception is altered in rather dramatic fashion. One would logically expect the sky to change along with everything else, but in vanilla Doom, it does not.

Demos
[[Media:e3m6icb.lmp|The invulnerability colormap bug]] on E3M6: Mt. Erebus

[Category: Errors and bugs] [Category: Stubs]