These maps are overall pretty good, with simplistic layouts and clean visuals! Sadly, I do have plenty of gripes with some of the maps.
Kart Krew Horizon is... a strange name for an actually really fun course. It's simple and I like the transitions in and out of the stormy areas. The bridge sounds are a cool touch! Perhaps a more suitable name would be simply be "Stormy Horizon", however?
Twilight Mansion is a pretty fun Ghost Valley-esque level! I liked the section going into the well and I liked the exterior visuals. Though, the merge in the mansion itself after the waving carpet section can lead you with a blind turn, and the visuals are actually rather lacking here. I'd have loved to see more love put inside the castle and well!
SIK Dragon Valley is cool to see, I really liked Super Indie Kart before learning about SRB2K! It's very faithful to the original layout, maybe a bit too faithful. The spikes placed right after a turn on the right is a bit tough to get by at high speeds- especially so in Hard mode, and Hunter Snake can really screw with runs of this course. I still rather like it out of nostalgia though!
Polar Paradise is probably my favorite out of these maps save for Horizon! The layout is fair and I like the spring placement near the end that can be risky to drift for, and the simple visuals lets the thick snowfall shine. The Penguinators are also a cute, fair hazard and I think we could have seen them more, maybe on the sidelines watching! I think a better music credit is order though. Who's Mega Drive music is this, where is it from?
And Scorch Desert, I'm sorry. I like the layout, I like the textures but *god damn* that heat haze is way too powerful for me. Having the whole screen wave so intensely through the whole course is way too hard on my eyes. I got a single lap in Time Trial before I had to call it.