Not bad for $20. Basic premise is repeated runs through the same level but with different characters, different abilities, which allow you to do different things through said level. The level gets harder the more you advance, with various objectives to meet along the way. You have 5 characters that each need to escape, first they escape one run at a time, then you unlock their objectives/stories, then finally you get all 5 to escape in the same run. Dieing isn't ideal, but just means you perform the run again. You still get all your points/cash though for more runs
It took me about a week to get all 27/27 objectives and beat it. Also, they released an update for Prey allowing New Game+ mode, among other things.
My loadout for the final 5/5 run: