Run around in the grim metal corridors, blast aliens and upgrade your equipment, survive.
Got the plasma gun ready today, I still need to work on the projectiles and their hit effect, but gameplay-wise it's working just fine. Personally I'm really happy with the model and texture, although during the first try the green part was dark metallic blue, I had to change it because Quake palette made it just bland gray :D.
Looks awesome.