Hello Evan,
I'm going to give this a 0. The theme could be considered unoriginal as there is already a Pipe map, and currently there is a submitted map known as "Tube." But the main reason why this is a 0 and not a -1 is the build. For your first map, it's quite well done and it's clear that a lot of effort went into it. It does seem to be a bit plain (And by that I mean the use of only stone bricks on the outside), work on adding more next time. As for the parkour, consider adding more variety to the jumps.
I wish you the best of luck! <3