Cryptkeeper is a game about being a literal dungeon master curating a crypt for adventurers.
Specifically, it's about descending into that crypt to fix it after the adventurers did something it wasn't coded for and bugged the whole thing out.
The PDF is 7 page with some great, charming illustrations and a legible but handwritten aesthetic.
Cryptkeeper runs on the Carta engine, so it's about building and traversing a map made of cards. Unlike other Carta games, Cryptkeeper has you reassemble the map from floor to floor. It also lets you build a hand of items---which are the same cards that you would deal with as encounters if you ran into them on the floor.
Discarded items turn into the map for the next floor, but you can't quite cheese the game into giving you a series of small maps. You need to encounter an Ace and a King on each floor in other to proceed, so you're encouraged to keep some items in your hand, but not to absolutely pack it full.
There are a lot of ways to lose Cryptkeeper, and the final win condition is pretty tight. Victory comes from savvy item use, desperation, and luck. However, losing isn't too bad. There are no major plot consequences to a loss, and it's easy to reset.
Throughout the PDF, the writing is consistently stellar, and the item mechanics are neat.
Overall, if you're looking for a single-player trpg with roguelike features, I would strongly recommend grabbing a copy of Cryptkeeper. It's easy to learn, it's engaging, and the setting is written so well that I want to read more material from the same universe. It's a great way to while away a little time, and a fantastic use of the Carta engine.