So I've played the most recent update of your level today and there is one major thing that I don't like about the execution.
The thing I don't like about this level is that you introduce the level elements to the player in a timed environment. Figuring stuff out might take a few tries for players or a surprise enemy may get them hit. It will cost too much time for a first-timer.
A solution to this problem is to have a non-timed rooms. These non-timed rooms will make sure the player knows what to do for up-coming obstacles. You can then apply those obstacles in the timed rooms knowing the player should be able to figure it out.
Some examples of obstacles in the first timed room that might be better introduced in a non-timed fashion:
1- Bouncing an egg of the wall to travel across the lava as mentioned above by NGB.
2- Regarding tulip, you need to bounce on the spring then spit the lantern ghost through the hole. On my first attempt, I got up to the ledge on the right of the spring where the opening was. Then I failed to figure out that spitting from there just made the lantern ghost hit the wall.
3- Those log platforms over lava with the fly guys are the ones that need to be balanced. I didn't realise as I didn't see the pointy bit of the stake.
4- The fact that you need to shoot straight up to clear a column of multi-colored blocks. A new Yoshi's Island player might not know the most efficient way of clearing them and waste time clearing blocks they didn't need to.
Some examples for the second timed room:
1- The yellow blob things. They may surprise a player and get them hit.
2- For the rotating platform, you need to be on the left side to make it go up.
3- The fact that you can bounce on those floppy arm ghosts. I guess it's kinda obvious but in a timed environment, people can panic and stuff.
Finally some minor annoyances in general:
1- The single block can be easy to slip off when trying to get the flashy egg block. Perhaps you can move the red egg blocks inward to make the platform 3-wide.
2- This slanted platform is kinda weird in the position it is at. I think it should be moved left 1 or 2 blocks or just switch it with another type of platform.
3- I think this pipe generating lantern ghosts could be on the left of these multi-colored blocks so that you won't suddenly get hit when jumping into the alcove.
4- Perhaps the egg block could be moved more to the right, near the stairs so that players who take the lower path won't lose time for eggs. And also lower the POW block by 1 block maybe.
5- These blue spikes appear all of a sudden when the camera pans upwards. Perhaps give more warning to them by having them also on the right wall so the player can see them at their height.
In the end I don't know if you will want to create more rooms for the reasons above so it is up to you. Just make sure the player doesn't get punished too hard for not knowing stuff while being timed.
Overall after getting to know the level it is quite fun. It is hard to make a YI timed level without being too easy or difficult because getting hit also decreases the timer significantly and was the most cause of time loss when I was trying out the level the first time. After I remembered enemy positions and stuff, it became much easier to manage my stars. Hopefully it turns out well.