So after playing this, I feel like it's on par with the well-known Sapphire romhack in its own way. Levels feel unique, atmosphere feels vibrant, and the music choice is also pretty good. One particular part I love are the shadows on the textures in the hub area. It makes things feel rich and colorful despite being a pretty standard hub area. Each level has their own unique theme and feeling that separates them from what you'd normally expect from your run-of-the-mill level themes.
My only critique really comes from the somewhat confusing path you take in the hub area, going from a tower warp in the distance to a pipe on the other side of the map to two regular doors with star requirements on different sides of the map. If there was more to see in the hub area to make travelling between areas less dull, that would significantly increase my view on the hub area.
Another critique I have comes from the difficulty spike on the last level. It definitely wasn't difficult for me, I have experience in kaizos and would consider myself to be well above the skill level the general public is at. But if a casual player were to go from 3 short, sweet levels to a pretty difficult casual level, they'd probably be turned off from finishing the romhack. If the difficulty instead gradually increased, I think that would aid the casual experience.
Regardless, I highly recommend this romhack. Another one to add to the list of romhacks to start off with.