Going for something a bit newer, I played a bit of Vessel today, and I’ll definitely come back to it.  It’s another puzzle-platformer, but it’s based mostly around fluid physics.  You’re either manipulating where water goes, spraying it yourself, or dealing with little creatures made out of water that can either help or hinder you, depending on the room you’re in.  Flip switches, open doors, move obstacles out of the way, etc.  It can require a decent amount of thought to get through a puzzle though, as it often depends on timing, the behaviour of those water guys, the order things happen in, etc., so it provides that nice oho-I’ve-figured-it-out satisfaction.