Great concept (and voice acting!), I think this has potential to be a full game. The level design was kinda hit or miss, for example level 8 was brilliant but levels before that I couldn't put pieces to the end without thinking. Perhaps using varied amount of hearts can fix this.
Some other small polishing tips would be to allow movement of blocks after they've been placed and better pathfinding but I understand you can only do so much in a weekend and it's still an amazing submission!