Great job on the backflip, as well as the opening hat flip.
Both movements are smooth, and the masking is flawless. Little details like the hat flip, while they take a lot of work, add quite a bit to the film. Although the camera movement may not have been necessary.

It feels that, for so simple a short, it needed to be condensed a bit. It felt over-long just to set up the "levels" concept and execute the flip. Some of the framing could have been better balanced, and the camera angles were mostly straight-on and flat, which didn't add much visual appeal to the scenes.

Sam's voice is good, but Steve's just doesn't sound as great, and his delivery of some lines killed a bit of the humor.

I don't think the flaws are in the concept, or even in the writing so much. But the execution can make or break so simple a concept, and this does need a bit more inventiveness in how it's shot and performed to stick out among similar videos that are out there.