I've reviewed a few local-multiplayer-only XBLIG over these first 700 or so days of this project, but perhaps none with the personality of "Hidden in Plain Sight". This game has a lot going for it.
There are a bunch of modes of play and they're all pretty varied. Games take a page out of "Where's Waldo's" playbook, with you trying to figure out which character you're controlling, then hiding who you're playing while trying to figure out which character(s) your opponent(s) are controlling. Let me explain: 2-4 players are dumped into a big field of computer controlled characters, and through action (and inaction) you deduce which one you're controlling, then do the same for your opponents. You have movement and attack commands and through observation can use them to figure out who you are, then watch for NPCs who aren't acting quite like the rest of the crowd to stalk to your opponents. It's a bit like a 2D version of the Assassin's Creed multiplayer, except with the added wrinkle of not initially knowing who you are either!
In one mode you are thrown into a field of identical-looking ninjas and win by either killing all your opponents or being the first to touch a bunch of statues in succession. In another you have knights protecting royals from ninjas. Yet another mode has you trying to walk/run to a finish line without giving away that you're not a computer-controlled character, while one player is a sniper and trying to suss out who is human and who is AI. There are other modes of play too, but those are the ones that struck me.
Yes it requires one or more other in-person players, but it was still awesome and worth 80 Microsoft Points if you meet the having in-person friends or family requirement.