The swirly and crazy design of the levels are a nice touch at first, but get boring quickly within the first 3 levels.
Its an exploration hack, with many different paths, yet you are not given much time to actually explore as the timer runs topo fast to actually take a look at everything.
The last level "cliffside descent" is the greatest example of this; you have to run through almost the whole level or else you'll run out of time, you have no time to enjoy the world that the author has created for you.
The design is okay, the author here uses one based on exploration. There are many paths you can take in each single level, making it interesting to play. Minor design flaws are here, like blind falls, but it's nothing too awful. As difficulty, it's in the middle of easy-medium; I'd go more for a medium though, since that last level was intense. But yeah, overall, a small hack that has a pretty decent design I must say.
Aesthetics are well worked. The vanilla elements are used in a neat way here; sometimes you'll see a custom BG made with vanilla graphics, some other you'll see many tilesets mixed together in a single level. Basically, it's a very varied one, probably one of the cleanest too: I wasn't able to spot a single cutoff nor palette which looked weird.
- Music breaks on accurate emulators.
- When sprites pass in some tiles, they act weird, like floating in mid-air in a straight line. Bright example, the first thwomp in the castle doesn't fall down due to said tiles placement.
Overall, 3/5. Not the greatest vanilla hack, but it's a very interesting one.