I wish I could say that I loved every second of the alpha. I stopped playing when I hit level 47. I love the concept, the art design and it ran fantastic on my machine. The controls felt surprisingly good for an early alpha. I had some occasional loss of momentum in the air and I know getting the physics right with moving and jiggling platforms isn't easy.
That said, level design past the first laser level (the static laser walls in a zigzag) was frustrating, uninspired and just too cluttered.
The square laser walls could just be replaced with simple wood walls to give the player a glimmer of hope of recovering instead of boring instant death.
The corridor of spinning lasers is just flat out boring, as you cannot judge their position relative to you easily. The corridor would be fine if there were a pattern for the player to find out and learn, but I guess implementing that with random trucks as platforms is hard.
The level with opening and closing circular laser windows is way too strict with the timing. The closing/opening interval should be a tad more relaxed. Also I almost quit playing the game entirely because I would clear the laser circle with a nice jump, only to have the truck steer away under me right after it clears the laser circle. As the slow motion toggle is useless when you are in the air, I felt cheated and frustrated because there was nothing for me to do and no way of knowing how the truck under me would act. The game forced me to do a jump in a certain direction only to have me killed. This wouldn't be that big of an issue if it didn't happen very often.
The levels after the lasers (bridge) need some work. Introducing a new type of obstacle (mallet, piston, pressure plates) is nice but mashing them together in to a single level was the point that got me to quit the game. The bridge levels already felt like I didn't have any control over the outcome and I would just wait for good RNG to ride out the level with 3-4 trucks. I would love to play levels that are a bit longer, have curves and fewer but more meaningful obstacles.
TL;DR: Fantastic concept, tweak the slowmotion system into a useful one (think franklin with his driving skill in GTAV), remove the lasers and don't let the person who came up with them design any more levels. Also, the later levels feel cramped and way too dependent on luck