Pretty cool icons, Suika Ibuki, I really love 3-6's icon, looks really well drawn.
Biggest gripe has to be both how the Thunder Lakitu looks in 3-7 and the Grinders in 2-2. They both could be drawn better. I didn't even know what they were supposed to be until I looked up what level it was.
Overall, good job! I'm going to be redrawing Baby Bowser in my level, 6-8. Expect it to be here soon.
Just so you know, I'm very active on the site anymore like I was before; I'm mainly on Discord now.