Edit: Switched this to negative since I can no longer play the game, and neither can anyone else using the Valve Index controllers. Game is otherwise good though
tl;dr Really fun, and doesn't feel like a game which should be free at all.
This game fits into the same genre as super meat boy or TrackMania stadium, in that the controls at first feel slippery and terrible, but once you master them, you can go back to the first levels and finish them in a fraction of your last time. It has the rare property in a game where it actually feels like you're learning something. Every level is a decent amount more difficult than the last, so the progression feels nice.
...Except for the last level, which brings me to the first of two complains: it sucked. The map itself was fine, but due to the mechanics of the level (which I won't spoil here), any mistake meant that you lose instantly. This level took the longest of them all. It felt like the developer was having a hard time making the game difficult (I got a bit of the same feeling from level nine), and decided to effectively make a time limit to artificially increase difficulty.
My second complaint is the camera. The game makes an interesting use of VR, where the benefit isn't immersion, but rather depth perception. It's pretty cool how quickly you learn to estimate where you'll land because figuring out distances is intuitive. My complaint however, is that often to go fast, you have to turn around quickly, something which really throws you off. It would be really nice if there was some way of using the HMD to rotate instead (but I can understand if that's just not possible due to motion sickness).
Overall though, if you have VR, there's absolutely no reason not to try this out. It's not going to be for everyone, but it's free.
