Alright, got around to trying each stage.
Worm Tunnel: Welp, it's similar to some of the stages from Lost World, but this feels a bit faster. Probably the only level where I felt a sense of going fast. No issues here.
Seaside Race: Man, what happened to the speed? I kept holding down Y, but 1/2 the time, it felt like it didn't make any difference. Rush, Rush Adventure, & Colors' sprint button actually felt different. Here, I didn't get that feeling that I was blasting through the level.
Seaside Beach: Holy CRAP, did that feel like it just dragged. It took me about 14 minutes just to complete the stage, & I didn't even get all the collectibles. The idea of being able to switch characters on the fly, while good in theory, really doesn't do much. You'll just stick with Sonic until "oh, gotta use someone else for a few seconds", then switch back. The stages felt like they were designed for just Sonic, but then they figured "eh, better throw in some parts where you NEED to use someone else". It doesn't feel like they were designed to balance out the usage of all 4 characters. Speaking of which, why is it Tails glides & Knuckles can't?
I also feel like this could've worked if the stages were shortened up a bit. Another issue was that 1/2 the time, I had no idea if I was taking a path that'd lead me to a hidden item or forced me to a new area where I couldn't return back to the split path. That's not a good thing, considering your levels are meant to be explored in order to find hidden objects to get 100%. It just makes me want to wait for a guide to be typed up/uploaded to YouTube. & why am I collecting the crystals from Crash Bandicoot?
Really, it isn't that this game is bad. It's rather "meh". If the levels didn't feel so long, MAYBE I might've waited for a sale, but I don't know.