Cool concept of moving the platform with the character! But it's pretty unclear what to do at first. I suggest making simpler, tutorial-like level to let players understand the rule first. Also for everyone stuck when dying, press R to restart. 

The idea is really cool. I think the first thing to change/fix is, in my opinion to add a restart mechanic after you fall of screen (currently I’ve just reloaded the page). It would be cool to be able to link/unlink to blocks by clicking them and have some puzzles based on that. Cool concept.

Great interpretation of the theme Joined Together! The art style is also quite cute. The only thing I would suggest adding is a way to restart the level, or a way of knowing if you completed it (I had to refresh page), but I understand the time limitations!