This was a clean and fun experience! The preview feature was a really satisfying mechanic to work with. I have a couple suggestions.
I would suggest showing where the spikes would show up when using the preview mechanic. Maybe use a purple square or something. I found that I would think a block would be safe only to jump into a spike. I could do the "math" in my head and track them before rotating, but I wasn't sure if that was intended.
I also found that on the transition between two levels I would exit on the right and emerge from the left. The problem with that is I am still holding the right movement key causing me to flip between the previous and next level, which was a little confusing. You could remove the collider after entering a level so that doesn't happen, unless back tracking is a planned feature in your game.
Otherwise, I really enjoyed this unique take on the theme! Nicely done!