It seems like every time I quit the game after playing, it says that I'm still playing the game. I can't re-open the game or anything because it says I'm still playing it. I try to quit steam but it says it must quit this game first. Usually I have to go into task manager and force close Steam, but that has caused some issues with steam lately. It does let me hop into another game. I'm just wondering if anyone else has any issue like this, and if there's a fix.

No, I haven't encountered that particular glitch. Game has been fairly stable for me aside from an audio bug that has happened on a few occasions. Occasionally the scream your ninja makes when you die will continue to loop in the background in all game areas and menus, and will not stop until you close and reboot the game.

Been playing a fair amount, and haven't had that issue yet.

@herbiebug: I'm glad I haven't gotten that yet... fuck me that sounds particularly annoying. I'm going to try a re-install and report back with my findings (I'm not very hopeful if you're wondering...)

That's one thing to try -- though I've noticed that the game does sync some things to the Steam Cloud, and so I wonder if your Steam might be having cloud sync issues.

The most general way to attempt resolving Steam client issues, if that's indeed the root cause of your issue, involves removing the client blob file and a number of others out of your Steam directory. I'd honestly be a little surprised if PC gamers haven't heard of, or had to use, this at least once by now, but it's easy enough to google up if you need more info.