Haha here's a tacky idea. Starcraft Doom.
You play as a marine. The weapons become this:
-Warp blade(Dark Templar blade, Replace chainsaw, you can only get it on this one level where you infiltrate some protoss structure),
-massive combat knife(The marines in Starcraft have massive power armor with maaasive hands so they'd probably get a massive combat knife, it will be more powerful than fists),
-Standard Issue pistol(Not gonna be a weak ass pistol either),
-Shotgun(Something colonists would use or whatever, also no Super Shotgun. I don't want it to be that obvious a TC),
-Gauss rifle(Yup, this is the weapon used by marines in the game, hopefully I can get it to use different ammo from the pistol),
-missile launcher(A slow firing anti vehicle weapon, or for taking out groups of zerglings

. It's not gonna fire quickly like in Doom but have a big reload thing),
-C10 canister rifle(The sniper rifle thing ghosts use),
-flame thrower(I guess the marine will find a firebat flamethrower kit or whatever and mount it on his suit, not sure if this is how it really works in Starcraft because all the firebat pics I've seen have the flamethrower built into the suit but whatever...)
Basically I want to make all the weapons do more damage so if there is multiplayer, it wouldn't take like 50 shots to kill a guy with the gauss rifle. I want it to be a bit more like Call of Duty but more shots to kill. And I don't want the pistol and the knife to be awful weapons.
There would be a bunch of missions. I'm thinking something like this:
-You start in some badlands with zerg everywhere and you have to get to an installation.
-So now you're in a zerg infested installation and you have to get a data disc or something random.
-Another mission is you infiltrate a protoss temple and get to steal a dark templar warp blade. It'll be in plain view but hard to get, like the soul sphere in E1M3.
-Then you infiltrate a Terran battle cruiser and do something cool or whatever, but in this mission you will be fighting enemy marines.
-Then some more missions here and there...
Basically the enemies would be Zerglings, Super fast zerglings with fast attack, Hydralisks, Mutalisks(Somehow if it's possible to make em fly around like agile vicious eagles and not act like Cacodemons that just float there), Infested Terran, Guardian(Yeah these guys can act like slow moving cacodemons), and Ultralisks(This will probably be a boss battle). All the zerg dudes that can burrow in Starcraft will sometimes spawn burrowed or maybe I can also have scripted events that spawn guys out of nowhere but play a little unburrow animation to surprise the player.
Terran enemies will be Marines, Firebats, Ghosts, and a Goliath as mini bosses. I'm thinking make the player fight like two Goliaths as a mini boss thing like fighting 2 barons of hell in Knee Deep in the Dead.
And for protoss you'll have to fight Zealots, Fast Zealots, Dragoons, and Dark Templar. Maybe a Reaver as a boss.
I'd love it if I can use a model viewer for SC2 to make some of the sprites, or get good looking drawn sprites if I ever get this project under way. Multiplayer deathmatch or whatever would be pretty cool for this...