(+3) GZDOOM CUSTOMIZATION.
(+4) GIT GUD.
(+5) HD BLOOMY WOOMY FOV FPS ASJDFNIFVDSA.
(+6) Secrets, hella secrets.
(+7) No episodic crap, straight up level after level.
(+8) Za weapons, za shootin, za movement... oh it feels so good!
(+9) By the power of source port, there's independent multiplayer.
(+10) Easy to learn, difficult to master.
(-1) Instead of having some less fun levels, it has an entire crap 4th episode.