Working through the rest of the stars...
Some real tight level design. Enjoyed the Tom's wall slow-mo climb.
Spring Mario...why did they have to bring it back. It wouldn't have been so bad except for the ONE CHECKPOINT. The part with the line of chomps. Ugh, shitty Spring controls were magnified 100% in that one checkpoint because it's do or die. bounce, bounce, HOLD A WHEN YOU LAND, OH FUCK YOU GAME YOU DIDN'T CHARGE AND DID A REGULAR BOUNCE NOW I AM GOING TO HIT THE CHOMP, GET KNOCKED INTO THE LAVA AND LOSE ANOTHER LIFE. Yeah. I'd say that was the hardest checkpoint in the game for me, but I hate spring mario and I hate glitchy controls in do or die situations so yes I was raging until I passed that part.
The 2nd bird level...on one hand I kind of enjoy these levels even though I hate motion controls. They feel like rogue squadron x pilotwings. Has a good sense of speed and cool locations to fly through. Otoh there are some glaring design flaws. In this one, after you go through the initial three holes in the wall you are supposed to hang left as it spins the world. Unfortunately this makes you COMPLETELY BLIND so you are flying blindy at a fast speed and then right on the spot where you come out of the left there are a bunch of poles and objects that will 1 hit kill you if you end up right in their face. I didn't find the level or 2nd star race hard, but I basically had to retry retry retry retry until I got lucky and didn't come out of my blind spot with a pole in my face. If I cleared that part everything after (and everything before it) was easy. But yeah, NOT SEEING WHERE YOU ARE GOING IS A FUNDAMENTAL FLAW IN A GAME.
I also have had some control glitching where Mario doesn't do a Z+A long jump even though I press Z+A. This often leads to RAGE on speed runs where I'm constantly trying to take shortcuts with long jumps and there are no checkpoints so like the speed comet in the giant galaxy at the end with the caterpillars, I get 90 seconds in at that last part with the spinning circle and catipillars and I'm trying to long jump each section and 1 out of every 4-5 times it doesn't long jump and I don't make the jump and die and speed run start from scratch again. I wish 3d mario just had a HOLD Z to RUN and press A to long jump like 2d Marios. Plus Mario could use the ability to run faster.
tl;dr I hate shitty controls.