Fixed gear wheel hard to spin
The chain looks a little bit too taut for what I use in my fixie. But I don't rely on my chain to stop the bike, as I am of the sissy kind that rides with brakes, so dropping the chain is not that bad of an issue, although it has never actually happened.

But from your video, there basically does not seem to be any slack in the chain, I try go with 1-2 cm (1/2-1 inches) when pressing on it. That means that you see some curvature on the bottom side, yours appears to be running straight.

This other question may help you get the tension right.