Oh wow! This level is gorgeous! I love the aesthetic you've got going on here and the palette is bright and cheery! The music fits perfectly well for a first level and the level itself is a decent length, too!
The custom textures look REALLY nice! They make the level really pop visually and stand out from a lot of the other levels I've played recently. The trees fit right in with everything and there's plentiful amounts of scenery scattered throughout the level. It's really visually pleasing.
The gameplay on the other hand needs some work. I played this through my first time and this same loop around the course 3 times and wondering "Where the
heck do I
go??" before realising that I missed the path to the left.
The way I would fix this is make the area you exit this section from way larger and make the entrance to where you're supposed to go WAY more obvious from the direction I came from, and you don't have to use arrow textures or anything of the sort for this. Simply putting down lots of rings, making the area more visible and larger at a first glance, and placing more enemies up there is enough to attract a player on where to go. Putting a checkpoint down is a good alternative to enemies and it doesn't hurt to have a few more checkpoints in your levels.
Now this may just be a personal problem since I almost never play the game with the vanilla physics set, but it really peeves me when people put downwards slopes in their level and then immediately follows them up with a 90 degree turn or a wall. I know rolling and running down slopes in vanilla is practically useless and doesn't really feel the way it does in classic Sonic titles, but this happened to me every time I started rolling down a hill and filled me with such disappointment.
Now I'm sorry that I'm about to let personal bias leak into my suggestions here but these might help with a better flow to your levels.
-Keep in mind that uphill slopes, sharper turns, and walls will slow your player down, this isn't a bad thing and can be used to make upcoming challenges easier to adjust to naturally.
-Uphill slopes and more gradual but more closed-in turns will slow the player down moderately and are good for when you need to give them time to react to an oncoming group of enemies or spikes just ahead. The steeper the slope or the sharper the turn, the more the player will slow down.
-Quarter pipes that the player can clear by having enough speed are good for stopping the player while giving them an outlet for the speed they've built up without the empty feeling of hitting a wall or turning so sharply that all their speed is gone. This is a good tool to use when you have tricky platforming coming up and you want to reset the player's momentum so they can platform without overshooting.
-Walls and 90 degree turns should be used almost exclusively as a last resort to block the player from going any further when they're going way too fast. They should be obviously textured and have a good reason to exist. These are for if you have a lot of tricky platforming that requires a lot of time and patience to get through or a boss if your level merges into one.
-Ring trails should be placed EVERYWHERE, these subtly telegraph to the player where they should go. Just like in a standard Mario game, these can show the player what kind of jump to make, how sharp a turn should be, and where they should be going, all while rewarding them without them even thinking about what they're doing.
-Downwards slopes give the player speed organically [meaning the amount they gain is dependant solely on what they do when encountering one] and are pretty much only good for doing that. Turns made after them should be given a wider berth depending on the difficulty of the stage so as not to make the player feel out of control when encountering them and give them a nice break from more focused platforming.
-Slopes in general act differently depending on how the player interacts with them. An inexperienced player will most likely just run up or down a hill without a second thought, but a veteran might try jumping off a slope. Uphill slopes will launch the player farther upwards if they have enough speed to start with, while downwards slopes will give the player more horizontal speed when jumped off of. There are many different things that can happen depending on how much speed you have and where you jump, but focusing on one or two outcomes is enough. Play around with this concept and see if you can come up with anything!
Some of this same logic can be applied to Kart as well and, really, Kart level design principles has a lot of overlap with Vanilla and the concept of flow. I've always viewed Sonic games as this rollercoaster you're able to play and influence, with a lot more freedom of movement as opposed to a set track.
Overall, this was a very nice map to look at but it could use some tweaks on the flow side of things. I really look forward to the second act!
