"Try to find as many secrets and map items as possible, kill as many monsters as possible, complete as many map objectives as possible, and explode as many barrels as possible, as quickly as possible. The player with the highest points or hi-score wins the game. Other than that, it is Doom."
It supports new gamemodes, custom wads, a addon pack with new monsters and even an online highscore table. More information and the latest version can be found at its official project page.