Courses
Spoilers exist below. Read beyond your current course at your own peril. Deafwave made a map (source).
ONE

c1 is a short beginner course to each the basics of the game.
The Wall Jump powerup purchased here allows both shortcutting the course, and access to c2.
TWO

c2 has several distinct sections, with three transition sections between two large rooms. The early course gives a hint toward secrets being available to explorers. A clear shortcut path is visible, but initial unavailable to the player.
The dash powerup purchased here allows for further progression.
THREE

c3 makes use of the dash to navigate throughout the level. In the first room, it isn't required to wall jump above the four spikes, but does make it much easier. The long row of spikes needs the dash. The second room also teaches the player how to use a dash out of a left wall slide to go left.
The Air Jump, aka Double Jump or DJ, is purchased from this course. Again, further course progress is locked behind the course's power.
We later return to this course with the blue blocks swapped out for orange, altering this course's path, which is a theme that will continue onward throughout the game.
FOUR

c4 is a much wider course featuring several gaps with spike lined floors. This course has the introduction of springs
The signature upgrade in this course swaps which of the colored blocks are active, turning off blue, and turning on orange. Progression after four is hinted at as we return to c3 that something is above because of the now solid orange blocks.
FIVE

c5 starts with a cliff edge and blue spikes blocking the player's path if we arrive before c4's powerup. The course focuses on wall jumps with spike floors once we reach the top.
The signature upgrade of c5 is the end of the first part of the game by power outage.
SIX

c6 is a short course just after a the moss mechanic has been shown to us. The first time completing this course is a puzzle due to our limited movement resources. This is the first course to have vines, which will continue to appear for the rest of the courses.
SEVEN

c7 is a mostly vertical course. It too is a bit of a puzzle to navigate the first time. Two inactive zippers greatly alter how this map is navigated once they are unlocked.
Progression following c7 is behind tree nodes unlocking the lower section of the map.
EIGHT

c8 follows the theme of puzzle to complete, in that the player needs to realize the first chamber isn't possible, and should explore elsewhere. Once powerups are unlocked, the course itself is still a lengthy puzzle to first navigate. This wide course has an entirely different path once zippers are enabled. The right wall has flipping orange/blue walls.
The signature unlock of c8 is Clone Dust, a resource that multiplies other resources gained.
NINE

c9 makes use of the tutorial path for learning moss, and is the first course to send us out into the main halls during it's completion.
TEN

c10 is accessed via zippers, and features many zippers along it's course. It starts with a pair of spike floor zipper horizonal flight, leading into a vertical shaft, and finishes with a 3 zippers that try to harm you.
FOUR - MOSS

c14 is the first course we revisit, and overgrown c4. It is first seen from midway into the course just after the credits screen. The start of c14 is similar to c4. The end is an entirely different route, taking us up away from the long spike hall switchbacks and instead taking us up and over on a route we see before getting to c14's entrance. This is the second course to be improved when the player realizes the teleport can be used.
THREE - MOSS

c13 is the second course we rediscover. c13 follows c14 style of being mostly similar layout of path, with a change at the end. On the turn to go left again, a difficult jump can be a roadblock to new players that don't know any tech. It's only just possible without the upper metal corner that is easy to miss, and a small amount of tech greatly easies it's path.
TWO - MOSS

c12 is the third course we rediscover. It features a lot of wall jumping.
ONE - MOSS

c11, might be the last course found in the game due to not having a teleport to it directly. It is now a much more vertical map, gaining the exploration area between c1 and c2 as part of it's course. It has several tight sections to navigate, requiring some finesse to get past.
FIVE - MOSS

c15, the last course in the game. It keep's c5's opening signature of cliff edge navigation, but loses much of it's interior, making use of the area above c5, and a few walls removed to continue through it's path.
See also
ToDo
- Minor description about where they are located (especially moss side 1 between 5 and 2).