Gears of War is a third-person tactical shooter that heavily relies on a pretty decent cover system. You play a member of Delta Squad, a military unit who are desperately trying to defeat a subterranean race of creatures known as the Locust. You are Marcus Fenix, a former prisoner and incredibly muscular soldier who looks like he's been popping steroids for breakfast from an early age.
Cover is a vital element of this tactical shooter so the first thing you need to consider when creating your campaign will be ensuring your game system's rules provide enough attention and benefit to using cover. Luckily most systems I've read which are in the simulationist vein have something in there on cover. Best to print out those rules and pass them out to your players. They'll take that as a bit of a clue. Especially if you don't include any other rules in the print out (except perhaps higher ground rules).
If you really want to play a Gears of War-style campaign, I'd come up with some excuse for regeneration (and huge muscles), perhaps involving genetic modification or chemical spills. Then, if you're playing World of Darkness rules you could take the werewolf regeneration rules. If you're using some sort of D20 variant, Fast Healing equal to level should work out fine. Stipulate that the healing factor only kicks in when the character is resting and you'll have players seeking cover so that their characters can hide and watch their health tick up - just like you need to do in the game when that health indicating cog appears in the bottom corner of the screen.
Remember that if you want to be true to the videogame (rather than just playing a game like it), you need to go science fiction but with a very Earth-like setting. I mean, I didn't even know the game was set on another planet (Sera) when I played it because all of the architecture and much of the flora looked pretty Earth normal to me. I had assumed that immulsion had just been found on Earth. Therefore keep most of the descriptive elements pretty modern (rather than futuristic) and ensure that the players know that simply evacuating the new planet is as unthinkable as simple 'evacuating' Earth. This is the characters' homes now. The fact that the characters can be baseball-playing heroes living in homes much like our own (before the Locust attack, that is) should help reinforce the kind of player protectiveness that comes from having your own home world attacked.
This is neither a "Simply shoot things" game nor a "Sandbox game". Therefore ensure the players have very specific, very simple goals, that should generally be broken down into sub-objectives. The first game ordered you to descend into the Hollow within the planet to detonate a Lightmass bomb but between the start and finish there were a lot of other objectives -- some of which only appear once a certain event occurs to the characters. Having a leader speak to them over the radio can help with this as they point out new duties and obligations.
This is a game that would work well with miniatures. Cover, after all, is a big thing. If you're going with this, I'd recommend creating chest-high walls out of paper that is shaped to look like Locust-cover points (metal fences) or rubble. In this way the players' miniatures may be moved up behind the cover, as can the enemies, ensuring everyone knows where the cover is and just how much protection it gives. Since all you need is a printer or, at worst, some folded up coloured paper, this should be easy to do. You could also use fish bowl decorations, doll house furnishings and real world rocks if you want to go all out.
Create an enemy the players don't have to empathise with. This game isn't about the "Horrors of War", in terms of sympathetic bad guys on the other side of the fence dying cruelly. The bad guys are BAD. Making them alien-looking creatures that spend their whole time attacking people with hardly an overhead Locust comment for colour, ensures that the players can gun them down and feel good doing it. If you're using a game with some kind of Morality system, scrap it, at least in terms of killing Locusts.
|I like to imagine these guys are watching a Christmas pageant.|
This is a game designed to be epic. Use massive setpieces. Have a monster swallow them up and make them tear their way out. Have them rush about on crumbling ledges above a bubbling pool of Imulsion. Have them outrun an explosion which nips at their heels and threatens to blow them through a wall. This is an action game. Go all out.
Anyway, a campaign based around Gears of War or including elements of it, should appeal to - you guessed it - Tacticians and Action Heroes the most.
Tacticians will love the cover system, complicated killing strategies (i.e. that giant worm thing) and focus on teamwork.
Action Heroes will love the explosions, gun play, running sequences and occasionally quite Big Bads that need to be taken down.
Explorers would enjoy the strange places, the apocalyptic wastelands of the cities and the underground places rich with odd architecture and alien beings.
Investigators won't have much to do here so throw them a mystery as part of the through-line to keep them interesting. Something like "What happened to your wife?" might help if they're still pretty keen on combats.
Communicators won't like this game. No real chances for social manipulation. While they might find much to like if they double as one of the other categories, odds are they won't really like it.
If you want to check out the trailer, you can find it here. If you want to read up on the TV Tropes you can find them here.