Excellent first map! There were a few details that were missed, like the aforementioned nonfloating rings, some missing pegging on FOFs, and ledges that were a tad too skinny, but overall this was a solid and fun level. It was a good length, too, which is hard to get right!
My biggest complaint is that the textures jarringly change theme halfway through and make the level decidedly uglier, then change back. The change doesn't really do or say anything, and I'd suggest making those rocky textures more in line with the established theme of the level.
That's really a nitpick though, and again, it's an awesome map for a first. Good job!