Revelations 2 is a lot of fun to play. An adventure game played from a third person perspective, there are basic puzzles to solve, blocks to push, switches to flip, abandoned warehouses to explore, and, of course, plenty of zombies to be killed, but the highlight here is the co-op play. Designed to be played by two players (you can play in single player, but it's nowhere near as much fun as with a friend), each pair has a somewhat asymmetric pairing, with one "main" character, and one who acts as support. In both pairs, only the main character (Claire and Barry, repsectively) can use guns, meaning they're the only ones who can defend themselves against the zombies, while the "support" character in each pair comes with a number of useful abilities, whether it's Moira's crowbar, which can break down doors (or zombies), or Natalia's, well, ability to point at things, which flags up useful items Barry may have missed, while also revealing the deadliest enemies, which are invisible to the human eye. Or at least, invisible to Barry's. Forcing you to rely on your co-op partner to make it through the levels, there's a huge emphasis on teamwork here, making it every bit as much fun for an experienced player helping a beginner out, as it is for two experienced friends.
In terms of accessibility, Revelations 2 comes with an adjustable difficulty level (including a casual mode, which gives you a lot more health, along with plenty of ammo and health pick ups), fully voiced cutscenes, full subtitling, and regular, automatic checkpoints, which mean you should never lose too much progress should you find yourself on the wrong end of a zombie. It is worth remembering, though, that Revelations 2 is a third person shooter, so some proficiency with dual analogue stick controls (where one stick moves, and the other looks around) will be required. As a survival horror game, ammo is scarcer than in other games, too, and there are no guns with unlimited ammo, so you'll need to try and be at least a little bit conservative with your ammo, although casual mode does throw plenty at you. Beyond that, if you can handle third person adventure games, you should be good to go here!