Put some hours into Invisible Inc. Turn-based tactical game with stealth elements and randomly generated levels. You attack corporations, disable alarms, fight the guards, steal valuables, use a thousand different gizmos, improve your characters, **** like this. . The main campaign can be completed over one evening, but after that there's lots and I mean LOTS of different challenge modes, and with random levels there's plenty of replayability in this. Different corporations have different types of defenses, so you need to adapt to that. Pretty decent graphics for an indie too.
Very fun little game. One problem I had is that difficulty is scaling a bit too fast and you can't experiment with different strategies as much as you'd like.