Kerkerkruip is a randomized dungeon RPG game. You fight through a crowd of enemies using different tactics and absorbing the powers of the defeated. You pick up treasure and magic spells along the way.
The randomization allows for immense replay value. Also, the game has an adaptive difficulty setting, so the better you do, the harder each replay is.
You have many options, like attacking, 'focusing', dodging, etc. This is the only IF game with such a well-developed system as of now (2015), as far as I can tell.
The game is relatively squick-less (no gross blood or other similar things). You face a variety of human and monster enemies. Each session can be completed relatively quickly (less than an hour).