I envision a system in which the player is “the disease”, but a disease along the lines of the aware recombinant cells from Greg Bear’s novel Blood Music. You must find some way to survive in a host long enough to alter your own characteristics so that you might move from host to host. Mutation characteristics might be beneficial to your spread in some situations (greatly reduced respiration needs, for example, make crossing water or staying submerged easier), and be detrimental in others (the massive bleeding sores all over you make it tough to come close to potential carriers). Each host is a temporary vessel, and the virus must protect it during mutation. A mutation timer indicates how much longer until the next change, then one selected trait or one random trait is added to the player’s “arsenal” of abilities. Perhaps they are some of the common zombie tropes:

* resistance to impact
* susceptability to fire
* immunity to cold
* echolocation
* speed

Whatever the change, you have to keep the host alive while the mutation takes place. When the mutation is done, the host (which was so useful before) is now hostile to your new form, being full of the old infectious agent. A new clock is ticking, and you must hunt, locate, and infect a new host. If you have the time, uninterrupted, to fully infect a new host, your ‘cellular memory’ moves to the new host, battles it internally for a few moments, and then takes control of most of the nervous system. Many memories remain out of reach, but body memory (climbing, working common devices, swimming) may all be available. At higher levels of functionality, access to memories such as facility routines (passwords, keycodes, repair or sabotage methods) might also be unlocked. If you lack the time to complete the infection, the cellular memory remains behind and the target host is just infected, and will not impede you in the future, but is not suitable as a host.

Sitting in a host for too long after mutation would not necessarily lead right to the “game over” screen, of course. Better by far to take away beneficial abilities gradually. Maybe the virus’ ability to draw nourishment from spoiled food begins to slow, or perhaps the old resistance to fire and heat begin to provide less and less protection. When the super-speed begins to falter, is shambling mindlessly that far away?

A virus with the right mutations could use the host’s body beyond its normal tolerances, eliminating the pain response, increasing metabolism or explosive muscle force, shutting down systems to ignore trauma. These actions would ‘burn up’ the host body, killing the host from within, but might allow the virus to survive a tough spot. Some security guard gets your infected electrician in a headlock? Use the host burn ability to gain greater strength, but now you have used up half an hour of the host’s effective survival clock. Better look for a new vector of infection!

The player might start out in a secret laboratory, having mutated inside a rat test subject. The rat has a few abilities, but the infection means the virus knows it must jump to a human host or perish. The rat works to escape the lab by chewing, climbing, and sneaking, and ends up outside, above ground, in the wilderness. It bites a camper who has been suffering through the rainstorm and wondering how to get back across the flooded river…

Where to next, virus? Your host is a hideous, mumbling shambles of a body with some survival skills that you have access to, but the best you can do for a weapon is a 4-D-cell flashlight.

Oh, did I mention that the security apparatus of the lab knows you escaped? And have you heard the helicopters yet? How about the other virus that also got out, the one that’s trying to assimilate you?

Perhaps one area could have a walk in freezer with fresh meet hanging from the ceiling from hooks. Player could possibly drag those out into the open to attract monsters who would then spend some time devouring it? Seems like a less gruesome way to set up a trap than cutting up a zombie.

@Ambience 327 - Condemned had ammo management that worked like that. You could hit a button and you would see the character pop up the revolver cylinder to show how much ammo is left in it, or pull out the magazine from the automatic weapon so that you could count the bullets. It worked very nice, but the firearms were incredibly scarce in that game.

The game did have really silly door puzzles though. For example, a padlock on a chain fence could only be smashed with a hammer, and an electronic lock could only be disabled with a shovel and etc.

Let’s say you are walking along and find a severed arm holding a revolver. You press a key to pick it up - and are treated to an animation of the character’s hands prying the gun from the cold, dead fingers, and flipping it open - revealing three bullets in the magazine, before closing it again. Now the player has to keep track of their ammo, or check it again as the progress. If they happen to come upon another bullet or two, they would have to take the time to load it - with shaky fingers caused by nerves - a random chance of dropping a bullet perhaps? (tink, tink - “aww crap”.) Then you’d have to pick it up and try again. A key press for each bullet on the ground would be a great mechanic - assuming the ammo is very limited. It would help increase the tension as ever precious second could bring that ugly zombie/moster you keep hearing into view.

I am definately liking the camper idea - what with being competent with tools, knots, fires, basic firearms, etc., you’d give the player enough options on how to go about things without being the uber-solder that takes away the fear factor.

Would also have some penalty… maybe you get covered in gore and are yourself more attractive to zombies, or only the ones that hunt by smell… or something.

Done too much, it would be hellishly annoying, but as an occasional thing it’d up the tension and make you feel less safe.

I’m a big fan of the first-person, no HUD or iventory idea. It would contribute greatly to a feeling of immersion and paranoia. Use just visual and sound cues, and perhaps wobbly controls) to give an idea of your condition. (Several games have vision become blurry when badly injured or exhausted, which would really ramp of the immersion and fear.)

Campers and outdoorsmen are also pretty resourceful, though they aren’t hard-asses like the now-typical combat vet. They can cut and chop, tie knots, lash poles, build fires, wedge doors, sharpen saplings, route water, read maps, climb trees, and use a few simple firearms.

That’s *simple* firearms. Even at Boy Scout camp they used to have a skeet range. I’m thinking of a shotgun, specifically - a very straightforward hunting firearm that forgives *some* lack of aiming. Adrenaline and stress should make it more likely that the character loses control and keeps pulling the trigger, possibly forgetting to work the pump and chamber a new round. Stress and firearms lead to mistakes, that’s why the military train with them so frequently!

You can add in the old staples like the dilapidated trapper’s shack, which might give you an option - launch a flare and then hide long enough for a (temporary) rescue to arrive. Not being able to do anything but move from inside to outside through a couple of broken windows, hide under a cot, then behind a woodpile, all while listening to what may be rescuers getting slowly closer in the woods would give me a pounding heart.

Oh, and there are uses for “secret weapons”. Do these suggest anything to you?

The Handyman’s Secret Weapon: Duct Tape
The IT worker’s secret weapon: leatherman multitool

@Tommi - I think that’s what we talked about when we went over the fatigue system. My idea was to use heavy breathing and panting as an indicator of growing fatigue, but blurring of the screen could be used as an additional cue of extreme fatigue.