It's auto healing. It takes 3-5 shots at most to get killed but usually its pretty quick. I'm playing on the second highest difficulty and I've run into some issues, in a good way, with dying or getting spotted. A lot of it depends on how you want to play the game.I'm trying to stick with the panther play style so usually if I get spotted I'll just let myself die. The single player has been pretty awesome so far. Can't wait to play co-op with my buddy.
I tried spies v mercs tonight and frankly it was awful. They made the asinine decision to not give mercs flashlights so it is hard as hell to see spies. They also took away basically all the vision modes that mercs used to have. Spies have all different goggle options including sonar which is just cheap. The maps are dark as hell and you can't see a thing. They are dark in a bad way. The Chaos Theory maps were dark in a good way. The spies also have real guns this time which is another awful idea. A pistol I would be ok with, but not machine guns. This is not the spies vs mercs we had during Chaos Theory when everything was fluid, smooth, fun and tense. This multiplayer just feels like you're going to get murdered every 30 seconds.