Awful. I'm sure this hack has been made in around 5 minutes and released without a proper testing.
The design is awfully flat, and the level themselves are short. On average, a level lasts 4 minutes, if not less. Some levels felt really confusing, especially the ones where the author replaced gfx with other sprites; "Shellshoot base" is the level which abuses that. The replacements, while you can try figure what they are, are not intuitive at all: everything is replaced with shells, which makes an already annoying level even more annoying. Definitely not a good design, this is a bright example of how bad levels are like.
Aesthetics is pretty silly, as I said before, the replacements the author did in some levels are totally random and not intuitive. As for the rest, the hack kept a vanilla feel, with a gfx assembling that overall could've been much better.
-The hack has breaking OW events: you can't get past 15 exits, and you'll be stuck on "Past World 2".
-The "level ender when no sprites on screen" is buggy: sometimes you can happen to get stuck after you've beat the "boss".
-Some major slowdown in some levels, such as "Shellshot base"
I have no idea if I should accept this. I'll let mods decide: eventually, poke me for the .srm, which has all the obtainable 15 exits so far.