Apologies if this has been done before, but in honour of Doom's 21st birthday, I hacked up a port of ZDoom for the Raspberry Pi! I used Chris's OpenAL fork as the base, and made some rpi-specific tweaks.
Here is a screenshot to prove I'm not lying:
Spoiler:And here are some screenshots of Action Doom:
If you don't notice anything different, that's because there are no differences! Hooray!
I will try to make a .deb of this for Raspbian Stable, but for the most part, you'll need to compile this yourself. It'll take quite a bit of time, but it's worth it.