Thank you for the constructive criticism! I'll try and address these issues to the best of my ability.
Originally posted by CounterfeitThe fire part, I am struggling because it's a little harder to keep track of the fact I can't interact with the Bowser fire or shells, and the Bowser fire non-interaction is making me more dismissive of the jumping flames that can hurt me. This is what makes the level harder for me than it seems it was intended to be. I think those Bowser flames belong in the BG so that the fire towers and jumping flames are front-and-center rather than obfuscated by the Bowser flames.
This was an issue that I tried to deal with by making the fire slightly darker, though it didn't seem to help much. I do think it looks better by removing it from the foreground. For the shells, I wasn't sure what to do, so I changed the frame and made them upside-down, as seen below. I hope this helps.
Originally posted by CounterfeitI think the contrast between the light grey hills, clouds, and the red sky is very strong and my left eye is hurting a little bit trying to play. Try any lower saturation combination of mahogany, sepia, and mauve (especially for the clouds) tones for your background that would be more agreeable with the red and browns dominating your level without becoming monochromatic... I am thinking similar colors to what you have for your grass/rails for your sky color, but after-the-fact altering your rails to look white-hot and grass to look charcoal-grey to keep it colorful.
I had trouble understanding what color you meant by "white hot." I ending up going with a light pink, which does make the rails look like they're hot. As for the background, I went with sepia. I'd say this is less hard on the eyes.
Originally posted by CounterfeitI'm not feeling there's a strong element that makes the level especially fun however. I did not get a feel that it was progressing in challenge or expectations of the player. The visual theme, namely the "where", is what is outstanding and unique. I think where this level might stand to benefit most strongly is the way of moving between train cars: your fire Pokeys and your turn block bridges can provide more diversity to that, as well as the consideration of Parakoopas and P-switches forming block bridges to get you between far-separated cars. There is a lot of potential to be explored here for the design to complement your already creative theme.
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Yeah... the level doesn't have very good flow, but how am I to change it at this point? The contest ends in 6 days, and I have to leave town until Sunday on Friday. I'll try my best to make the level actually fun to play, but it might be tight. Also, having both decorative Koopas and sprite Paratroopas might be confusing. Glad you liked the theme, though!