First off, the art and music your team have made are outstanding! Very well done, it looks and sounds professionally made. The main puzzle mechanic of sending items to and from each side seems interesting, and you definitely could explore it more and come up with some very tricky puzzles.
I'm not sure if I missed it or just didn't get far enough to see it, but I didn't notice any gameplay applications of the different scales of each side. I thought that if you trade a block on the big side to the small side, that it might still be a big block on the other side. But as far as I could tell, the scale of everything stayed the same (relative to the side it was on). It actually didn't feel like the two sides were different scales for me. They both feel the same as each other, except Pixel's side is just zoomed out more.
The two characters also felt the same to control. Relative to the grid lines, they both seem to have about the same jump height. Although Redd definitely does feel slower for horizontal movement. Overall, I found the movement quite frustrating and unforgiving. For tight platforming, you need to use a lot of tricks to smooth over small player mistakes, and show feedback to the player to make it feel responsive. A few of these tricks you could implement are things like coyote time (allowing the player to jump for a few frames after walking off a platform), higher jumping if you hold the jump button (this one is easier if you reverse it, and make jumps shorter if you let go of the jump button early), and using a movement envelope for horizontal movement (having consistent times for reaching max speed from standing still and the time it takes to stop completely from max speed).
I'm not a normal player though, and I definitely think I care way too much about game feel. Still though, your team have made an excellent game and you should be proud of what you've accomplished in the 30 days we had. I'm looking forward to seeing how guys will grow :)