The first gap is definitely the hardest part since it's slow to build the path and you can't go up, but once you get past that and a bit of the ways up, there's not as much of a challenge as it's pretty easy to speed upward with the unlimited pebbles. It's unfortunate the level design didn't give much variety as I just stacked straight up. I did notice that sometimes I couldn't jump for some reason. It could be some input delay after placing a block and ate the input. I did have fun with it though and beat it on hard, so good job.