I made similar game but you kept it simple. You made nice effort in explaining mechanics.
I would prefer little bit faster text speed and maybe skippable.
I if you maybe changed direction on wall impact with character it could open much more possibilities in making levels.
In one level when placing blocks on the restricted area it would reset the blocks value to starting value -> infinite blocks bugs.
Overall nice game. If you added some more mechanics it could make a nice puzzle game.