Hmmm
It's clear you spent a lot of time on the animation, and that pays off well. I'm confused as to why you didn't actually sync the vocals with the mouths, since you put so much time into the rest of the cartoon.
It's really really hard to understand what the characters are saying, it all sounds muffled. I'm sorry to say that you'd do well to have a running subtitle over the entire thing. Partly its the audio compression, but partly it's that the voices were not enunciated well.
The frame by frame was done superbly, for the most part. I think the whole soda-can-portal-to-the-robot-planet thing was a bit odd... I think more effort could have been spent on scripting his arrival to the robot world.
I'm interested in seeing where you take this series, but you do need to work on it a bit more. That said, I gave it a solid 3/5 in the portal rating, because it's definitely "Not bad, in fact, I kind of liked it!" Work on the things I mentioned and it could easily get up to a 5.
Good job, keep it up.