Lightbringer.

This was released a while ago on PSN and browsers I think, but it recently came out on Steam and it's still pretty cool. Light governs everything in this game, if something isn't illuminated and visible then it doesn't exist. Which makes for an interesting dynamic as you're trying to get to the exit doorway while also trying to move all the lights you to build that path to get there. Sometimes this means dropping down somewhere to get a key and then you need to find your way back sometimes, it means getting to another place so you can get access to one of the lamps to point it in the right direction. Clearly it's going to get more devious as you get further in but it's had a pretty good ramp up of introducing concepts as it goes.

The main gripe I have is more that I'm a moron that keeps mixing up the jump and action key which on a keyboard is 'A' and 'S' and when putting a light down could mean the difference between surviving and dropping yourself into a bottomless pit of doom that becomes rather irritating. There doesn't seem to be any checkpointing mid-level which is fine for now while the puzzles are relatively simple and short it could get to be incredibly punishing not being able to save mid level and just go 'yeah this is where I need to be, I don't want to have to do all that again just to get back here'. Anyway it's a cool game, clearly a lot of scope for more insane levels in the future as I get to the second and third worlds.