great level, especially for your first. i'm also really glad that you watched sev's tutorials and did some research before posting a level, i saw where you used that information and it really does make that much of a difference. the only complaints i have are mostly visual, with a few flow issues on the side - but rest assured, nothing jarring that makes the level unfun.
let's start visual. overall, there's too little variation in wall textures. take another look in the 'textures' folder in srb2. you'll find a ton of useful new textures for walls, including the aptly named "gfzwall." rather than seeing bland checkers all the time, these textures add some life to the section. the caves looked nice too, and i really appreciated the ceiling variation and landmark decoration you put in some of them, but the next step is to slope the ceilings - it helps more than one might think. i see you did that for the very beginning of the level and i have to say it looks nice as h*ck. my last thing for general texture issues is water fof's - recall in the zone builder tutorials that you need to lower the floor of the water fof past the floor of the actual stage. otherwise, the fof's floor texture shows on top of the actual floor texture, and it looks messy.
as for smaller-scale things, there are a few walls without textures but most of them are pretty out of the way, and some of the lakes have the greenflower grass texture on their floor. mapthings were placed really well, and you made them synergize strongly with the different floor textures - surrounding flower patches with flowers, adding trees on top of small flowered hills, etc. etc. however there were some mapthings arranged in a line that weren't quite aligned perfectly with each other, if that makes sense. for these tricky angles, it helps to draw a linedef from the starting point to the finish, and then place the mapthings along that linedef (you can even delete the linedef after too!).
now finally moving on to actual level design, this level might be one of the best first levels i've played. i can tell you're kind of experimenting in this level, but you're doing so with the player- not the creator. that probably doesn't make sense, but basically what i'm trying to say is you're setting up different jumps and exploration routes for the player so that you can see how they react, and then build around that. i think. which brings me to: the amount of new stimuli you throw at the player is just right. it's not a boring "jump to this platform and then the next" level, and it's not a confusing mess of different mechanics. it's simple and fun.
buuuuuutt it does break flow sometimes. at the very end for example, you require the player to go under a wall through water. from either route, you have to stop and jump/drop down, and then spring back up to land. it's not *too* bad, i just wish it was the bottom route punishment and there was some sort of top route to get over that wall that doesn't break momentum.
oh- and don't worry about it being a short level. it took me two minutes to beat it on my first go, and speedrunning as amy i managed 34 seconds. those are fine lengths for a level.
now time for individual issues that i didn't know where to stick in my essay of a review:
- too many spin barriers to get to secrets. nospins can't get to these. you especially should include a nospin route to the emerald token
- you spawn too close to the wall, the camera starts weird
- speaking of spawn, player 1's spawn should be centered. you spawn a slightly to the side, i assume this is to account for another player but you should build spawns off of player 1's center spawn for singleplayer levels
- the path splits are good and create replayability, but the first one is lacking. there is no incentive to not take (spoiler) the left split, because it is significantly faster and significantly easier
- the super tall spiral hills are really nice, but there should be more reward for climbing them, and the one right in front of the signpost should not be there because it blocks the view of the signpost until you're three feet away from it
- after the lake with the whirlwind shield in it, if the player takes the left side of the canyon rather than the right, they get punished. simplified, it's essentially pick-a-path design
- the tree from the path split is out of place for this level - the rest of the level conveys a more flat, plains/canyon feel
really fun level, there's a lot of good stuff in it. this certainly is a first level you should be proud of
