I played through it without watching the video and that was the result. The level was okay, although it was mostly confusing. There was a wall that would shut down at the very beginning and there was another door that had a wall high enough to where the player was only able to see what was above it. Other than that, it's pretty tame and kind of what you would expect from someone who's recently started to map for Doom. But there's some tips that you should consider.
Mark the doortracks of functional doors with "Lower unpegged". For some reason Id Software did that which resulted in the tracks remaining stationary, so it's tradition to mimic it.
Look up John Romero's mapping design rules.
Placing the exit sign near a trigger/switch is also good practice for letting the player know that they won't be able to go back and there's no more of the level to be explored.
Try playing around with lighting a little more. Maybe put in more prominent light sources because the lighting overall seems to be flat. Don't be afraid to make the darkest parts of the level contrast more with what's producing light.
It's a pretty respectable map for a new mapper like you, but don't be afraid to experiment more!