This is a really clever use of the theme and I absolutely love the art style you went with. The 2D in a 3D world concept is always great too. As many of said though, it definitely needs a tutorial and the game is going waaay too fast at the start. With random spawns, the first jump being attainable was not always obvious (at least it didn't seem to always spawn with a block in reach on the front side) so it made me think that I had to place a piece to make the first jump of the game. But because of the timer, that is physically impossible.
Once I figured it out though, it was a lot of fun. Trying to think strategically about when to place blocks and where to head with your jumps makes for a great combination. So with a smoother introduction I think the game could really shine. Well done!