I really enjoyed the animation as a whole. I think the story is one we have seen/heard time and time again, but your version of it is a simple easy to explain short, whereas movies would take a hour and a half to tell this same story. He is on Phineas and Ferb levels of intelligence.
I like the characters, they are a bit bland but the main duo are fun and the shape language is spectacular on them. I like the voice of the characters, however the main character Glenn not speaking or uttering a sound in the first half was strange, since he wasn't mute and talked a few scenes later. I understand he is shy but at least a grunt or gasp would of made him feel more human.
The music choice was alright, it fit the time its set in, and the sound effects were put together well. My favorite part by far is how good the animation quality is. I do enjoy the simple style of it, and something I noticed was the blinking did look a bit strange, it took me some getting used to. The 3d was blended in nicely as well.
The writing is not my favorite, again very predictable and every character serves their purpose and that's it. The execution is superb, great work man.