I got the door unlocked on stage 6 but couldn't get past that point, argh!
yeah the stage 6 is basically just a joke. but with fast enough movement it is definitely possible
one critique, I was annoyed when I grabbed 1 box and moved to grab another box, but it dropped the first box. Then I grabbed the first box, but then it dropped the second box. Killed me a few times.
i know -_-there were multiple things that needed fixing but there's just not enough time.