ReThink
This is an OK puzzle game with a major problem: It has no justification for being in first person. The entire game would have made perfect sense as just a series of 2D puzzles. Indeed, it would have worked as a simple 2D mobile game.
There is no story, no exploration, no adventure. It's just a series of puzzles, all of the same type: You need to get light beams from one square to another using a limited number of reflectors/converters. Sometimes there are several possible solutions to a puzzle. The game does look nice, and the soundtrack (there's only one track, it seems) is a pleasant enough accompaniment. But it's all just window dressing. If you're looking for a Portal clone, this is absolutely not it.
It's worth mentioning that it's not at all obvious how to use the mouse and keyboard controls (there is no gamepad support). The on-screen "tutorial" just confused me and it took me a good 20 minutes to figure out how to get through just the first trivial puzzle.
Also confusing is that this is actually two games in one. The developer completely rewrote the game and then shipped both versions together. I guess they were embarrassed about the state of the original, but not embarrassed enough to remove it entirely. I played the new version.
So, what's the bottom line? The puzzles are just OK. The later ones do get a bit challenging, but there's nothing especially clever about the solutions. The real problem is that the game misrepresents itself by dressing up as a first-person puzzler. I would not have spent time on what is essentially a simple 2D puzzle game, and I imagine most people discovering ReThink would feel the same.