Survivor Squad, product of Endless Loop Studios, is a zombie apocalypse lover's dream. The game sends you into hostile environments full of mutants and walkers with 1-4 squad members. If the squadmates die, then that's it: they're dead. Yes, this game does feature permadeath of it's randomly generated characters. The game was a blast and I give it a full recommendation.
You view the maps from a top down perspective, and you choose where to go from a waypoint-based map. However, you can only see what the survivor's have in their line of sight. There are some items that cover more area (sensors, cameras, etc), but it seems like zombies can just appear out of thin air sometimes.
While you are limited to 4 members in a squad, you can have more members leftover, like a reserve guard. These guys come in handy, as sometimes your bases will be attacked by a horde. This isn't a big deal at first, but the game becomes noticeably more difficult as the game progresses. Objectives like alarms, spawners, bosses start to become more prevalent and need to be dealt with quickly. Reloading can be deadly in these situations, but luckily ammo is infinite. While normally I don't have much love for infinite ammo in a survival game, the mechanic tends to work with Survivor Squad, especially considering that one has to deal with up to 100 zombies, all alerted to your position.
Some minor downsides to the game are the music and the atmosphere. The music changes to a loud, rock-like noise whenever you fight a zombie, then quickly fades away if you don't kill another in short order. The music itself is more of an annoyance, so eventually I just muted it. The game provides visual cues when combat is going on, so it wasn't needed for that extra alert. The atmosphere, while good, lacks a somewhat confusing part: there are no women. None at all. There aren't any female survivors or walkers (although it's hard to tell walkers from each other) and it seems a little odd. The game is still in development though, so maybe it has yet to be added. The good news is that they'll probably have multiple voice actors, because each male seems to have a different voice. They're all the same 1 or 2 word responses, but it helps identify the characters from each other.