So far this project is pretty bad after I played the demo of this episode so heres my overall thoughts and review of this project.
Starting off,everything from the levels,difficulty,bosses and world map is pretty terrible.
The world is poorly made with barely any scenery on them,along with cut offs and awkward design choices. The world map incredibly barren and bland at best. Even the lava and water on the map hasn't been fully placed leaving just a black void outside of them which I thought was a pretty lazy and illogical design choice. I can see you tried to place castles as scenery on bowser's world but you didnt set the option for them to be always visible on the world map to make them visible in game. The world map wasnt good at all.
Now for the levels:
oh my god....Where do I even begin.....
lets start off with the "atmosphere" or setting of the levels.
Starting off the castles, they were all barren and bland like the world map, Lacking background objects and decoration. They just all felt lifeless and boring.
for other levels like ember forest, It doesn't remotely resemble a forest what so ever. I dont understand why you didnt use the smw tree bgos. or hell even the smw forest background over the out of place smb1 night background. The grass tileset also clashes with the lava. Also custom graphics would be a huge help with how your overall levels look. But right now they all look pretty bland,boring,lifeless and unattractive. I don't see why you are limiting yourself with the vanilla ones.
Take this image as inspiration for ember forest. Using custom graphics can be incredibly useful.
now for the level design:
these level's contains bottomless pits galore,unnecessary lava pools,Unfair npc and level design,dick moves and trial and error along with kazio traps as a cherry on top. The difficulty and poor design of the levels got so bad that I had to Turn on at least 6 cheats, Something that I rarely do when playing episodes.
Your levels and its problems with level design and its atmosphere/settings. Some areas was so unfair and impossible that entire sections had to be in a single screenshot.
some enemy and obstacle spam. I rarely got out of here unharmed.
also wart for no reason what so ever....
More enemy spam, And the platforms are sloppily placed.
3 big boos,1 tiny room.
are you kidding me?
nice a birdo boss fight in a flat empty room...so fun.
its not a forest its just a giant lava lake. Also being forced to jump on a kamikaze koopa while dodging bills and having the left camera disabled. Thats not impossible and frustrating at all!
i didnt even bother bringing the key back to the start of the level...
some of the blocks in this section are impossible or incredibly difficult to jump on. They also scroll too fast. also obligatory lava pit....
the spiked wall that chases at the begining of the game is just poorly handled also how the hell are you supposed to grab the yellow switch and hit it without getting killed? DId you even test this???
Now for the worst offender, trial and error the level.
In "shyhatter" Village its impossible to leave this place after getting the star. I couldn't go back to toad town and finish ember forest. I had to cheat in order to get out of this place. Also whats with the subplot with elder tenda?
Overall This project so far is not looking good. But don't let this bring you down. I know you are probably a beginner so this is so far understandable. As bad as the levels where there was some interesting concepts and ideas put into it. But they were unfortunately poorly handled. I am looking forward for this project to be improved in the future.