To add on to this, I really enjoyed the game's core mechanic (it's like super mario maker assist blocks but you have a limited supply and they also affect your controls), but I also struggled a lot with the challenges presented. I didn't see too many comments about this so I'm not sure if most people didn't have similar issues or they didn't do the final segment. Here's some thoughts about my experience with the game and some suggestions for improvement:

Based on the segment that introduced places where you can't place blocks, I assume you wanted to teach the player about putting a block down while jumping since when I went back to play a second pass through the game I spent a while trying to figure out if it was possible to do that segment without that knowledge and it seemed impossible. One thing I tried was to stand on the edge of the left block then put a right block next to it and remove the left block, but it looks like your collision boxes have rounded corners and I just ended up sliding off of them. Also, I assume the intended solution for the final segment is to have the space bar be level with the upper ground and put the left key to cover the downward fireball cannon and then just walk straight through, since you had the width of that area be precisely the width of the space bar. Please let me know if these were wrong assumptions since I'm curious if I missed something obvious!

Suggestions on mechanics based off of that:
- Add two types of leeway for placing blocks. One type should be if you place a block so that the player partially clips into the top half of it, you still allow the block to be placed and automatically pop the player up. The second type of leeway should be if your block partially clips into existing tiles by say 2 pixels, then it should automatically push it out into open space if it exists. Especially when playing the last segment, it felt too tight to place the space bar and it felt like I had gotten the core idea down and that the execution requirements were unfairly precise.

- When the player drags a block out to place, slow time down by a factor of 0.3 to 0.5. Advanced techniques like gaining infinite height with just the arrow keys is really cool but the player's jump isn't floaty enough and actually executing it ends up being fairly frustrating. The leeway described above would also help.

- I assume either the button blocks have rounded corners in their collision box or the player is a capsule collider and that's why you slide off on the corners. I think the intent was probably to allow you leeway when jumping onto the blocks so you can get up the corners more easily, but since they're not very wide, it's easy to accidentally slide off too. If the blocks are the ones with rounded corners, you could probably add an extra line collider at the top that does one-way collision so that you can still get the effect where players slide up and over the corners but not slide down them.

I ended up writing an essay :p but I really enjoyed the game's idea and actually implemented a prototype similar to it (except you can just drag one block around and it doesn't affect the player's controls) somewhat recently. Hopefully I didn't totally misinterpret stuff in your game and that this was helpful!