pixel dungeon series is very pick up and put down-able. they’re all roguelikes, f/oss, with different variations for different game experiences. right now i’m playing Experienced Pixel Dungeon because it introduces a character class I really like (the duelist: rather than being a straight fighter or a caster it’s a melee weapon fighter where each type of melee weapon comes with a different special attack).
The fun in these is that for each variation the gameplay will be similar, but have different elements added. There are some that have skill trees, some that have new PC classes like I outlined above, some that are just basic nethack/rogue clones with a GUI, and a bunch that I haven’t tried yet. And they’re all offline, turn based, and let you save at any point so you can just pinch it off and get back to whatever you need to do in an instant.