Not gonna get into the level's overall quality much here since I'm not really the best at articulating these things beyond "get some experience and experiment with different ideas and ways to design."
So I'll focus on the formalia and straight-up oopsies.
- You used Dragon Coins instead of the Dragon-Coin-resprited Star Coins
- You used the npc-192 checkpoint, which has been deprecated in the SMBX2 MAGLX3 build, which is the one suggested to be used for devkit compatibility (and which you even USED in order to get those switch palace blocks for the dragon coin)
- SMBX2 MAGLX3 build also has a SMM flag checkpoint by default. NPC 430.
- On that note, there's also the deprecated lineguides and old grinders here
- SMBX2 MAGLX3 also has a collectable trigger NPC which removes the (never even present) need to drop goombas into a pit to trigger proximity events. I suggest you use that you-know-where. The "Activate" event trigger will happen as soon as the npc comes onscreen
- I didn't know what to do here, so I jumped on the goomba
- ^^ instead, perhaps block the path off with NPC-only blocks and link the wall disappearance to the statue's death or something
- I thought the koopa resprites were just shells I could pick up, so I got hurt by them
- Are there even any mushrooms made in this factory?