Hey Strawberryshinya!
Here it is, finally. Uhm, I just wanted to say first that The fixes I made were very small tweaks really. You did a really good job, and I had a tough time finding any actual "errors"
Also, the thing about the heads being too big compared to the body is arguably just style. I know that bigger heads are actually quite common in anime, but for this critique I just wanted to do more anatomically realistic proportions.
Biggest problem really was that the poses were too stiff, and I made really minor tweaks to make them look more relaxed I guess.
Hope it helps, and good work!
Here's a link to the youtube page, in case you need it to download:
Paintover Video