I saw the game at TooManyGames, and decided to download it at home. Here's my overall thoughts about it after playing for 40 minutes.

The character art style is great and I love the pencil sketch look, but it clashes with the level's very basic blocky style. If you maintained the art style beyond just the characters, it would look much more visually pleasing. Some background art and variety in color shades can go a long way. As for gameplay elements, there isn't much visual distinction between the blocks you can pick up and the ones you can not. This also makes it difficult to tell what you can stand on while switching characters and what you can not.  The levels themselves could use better art.

The physics are a bit clunky and I find myself contantly getting stuck inside blocks or through the floor, because the teleported adult holding the block would phase into me. This can get annoying quick as I would constantly need to restart the whole level. You should at the very least add checkpoints between sections.

The gameplay as the child is fun and has a great, responsive control scheme. However, playing as the adult overall feels really slow and boring, and slows down the progression a lot, especially when walking across big open spaces.

These are just some of the bigger critiques with the game. I think you have a great idea here and the story is really interesting, but playing I can not tell which has the bigger focus, the story or the gameplay as you get a bit of both as you play the game, but you never really get enough of either one. This is a problem as I quickly lost interest to keep playing because I do not feel satisified enough in either case. I think the levels are big in size but the puzzles themselves are small and easy to solve. There is only so much you can do with moving blocks, and the story is revealed slowly one detail at a time. You can easily fix this by focusing more on making the gameplay more investing, either through more gameplay elements or quicker pacing. You could also add more detail to the story, maybe through more, longer comic book panels or some sort of animated cutscene between levels.

In closing, I really like the idea and what you're going for but to be completely honest, the execution is just not quite there and it causes both the game and the player to suffer. I hope this did not come off as harsh as I only want to share my perspective as a player! I hope to see more from you! :)