It seems really well put together. in the 50+ deaths I did not notice any bugs. Jumping is smooth and consistant and I really like the simplistic style you went for.
The perspective being from behind the cube gives the game an added layer of depth as opposed to things like Geometry Dash and also provides a great challenge which I really enjoy.
The only question I have is that, is the last block of the level actually passable? It may be I wasn't precise enough though.
All in all, I really enjoyed the experience! :D