Thanks for playing!
Haha, those are cinder blocks. In my idea, this was a building in construction, and the Void is sucking in all the construction materials, so I modeled some itens that make sense inside this idea, and to make the game harder I made it in "levels", so each level the materials get smaller and it is harder to pass.
And about the issue, you tried holding space while jumping? I never found an impossible jump while testing.