Hill-Bit Land
Aesthetics: 4/10
I liked the use of 8-bit graphics in this level, especially the Bowser Jr. gfx. You also put Bulby's music to great use. However there were more than a few flaws I noticed while playing the level. For starters, the grab animation for Mario doesn't exist, in that place there's just a black mask. Then there's the fact that Luigi is still completely 16-bit, ruining the atmosphere when you play in with two players. Then there are lots of effects that are still 16-bit, for example the door animations. I also don't recommend putting Kuribo's shoe in, since it's using a hardcoded graphics that is always the original shoe graphic when the player wears it. The star gfx was also 16-bit, as well as the flowers at the checkpoint and the checkpoint itself. I really advise you to avoid doing this, it only creates clash. There was a general lack of BGOs, although this can be somewhat excused since it's 8-bit, it still felt a little empty.
NPCs: 3.5/10
The enemy placement was okay, during some parts there were all sorts of enemies just randomly thrown in. The Bowser Jr. boss was almost impossible to beat because the bombs were too big and you couldn't even throw them back. After you beat the Bowser Jr. boss... no. Just no. Don't ever do this. I know you're trying to simulate a cinematic effect by making the earth shake, but don't do it with POW block generators, please, especially not at this rate. Another thing was the piranha plant of the level that came out of a pipe... but in a really unusual way.
Not only does this create cutoff, it's also unfair to the players who don't expect a piranha to come out of the middle of nowhere.
There were about exactly none coins in this level, except for the one's in the blocks at the very start and the very ending of the level. I suggest you add some of these.
The powerup placement was aight, except for one point this level was good to beat with the given powerups.
Gameplay & Design: 5/10
This level was a nice play, I liked the thing you did with the NPCs, I actually had to laugh at the Kuribo Goomba, and although the SMW Goomba clashed really hard, I still found it funny.
The Bowser Jr. boss was nice, except that it was really hard to beat, as well as the last boss of the level. The story you tried to implement was interesting, although your English could still improve a little so it becomes more understandable to the player ;P
As for the design, you made one of these levels where you start off in some plains, then make your way through the level, to end up in a castle in the end and fight the final boss. This worked well for the most part, although the first section was a bit inconsistant where you first went for some plain-styled level, then it turned into an "athletic" level, then it went back to plains, then a spiny field and then the followed the first boss. What I really liked though were the references to SMB 1-1 and SMB3 1-1.
Over all, this level was nice, it had a few flaws, but it was nice.
Final score: 4.4/10, moved to Average