In World 3-Tower, there's a Mini-Mario Pipe near the beginning. I had just gotten to World 4 by the standard "beat World 2-Castle as Mini-Mario" thing and I still had the mini-mushroom in effect, so I decided to check out the pipe thinking it would lead to the secret exit. However, all I found there was what looked like a dead-end with a Mini-Arceus.

...Really? You're putting an Easter Egg that out-of-the-way? I suppose that's the point of an Easter Egg, but it's still kinda cheap, because people, like me, might look at the mini-pipe and think either a secret exit or a bonus room.

This is absolutely amazing work here. Seriously, this is far and away the best NSMB hack I've played. The graphics look good (even if a lot of it is just Wii tilesets), the level design is top-notch, the world-maps look nice, the custom music is pleasant (I wish you had put in some more new music, though), and the creativity in some of the levels absolutely blew me away, such as how you used the snake blocks in that one sky level, or the pipe maze level with water you could swim up. The only negative things I have to say are a few questionable design choices here and there, such as in the autumn forest ghost level, where it's possible for the player to unknowingly screw himself over by collecting some coins before he realizes that there's a p-switch. These are just minor things, though.

Final score: 8.5 out of 10. Once again, phenomenal job.

Positives:
• The graphics are out-right amazing. Many hacks attempt and fail to recreate a modern Mario feel, but this hack succeeds to capture the feel almost perfectly.
• The custom musics are very well implemented. No track is too loud or too quiet.
• Every level has a new challenge. It's very common in fanmade Mario levels to find a complete clutter of random challenges, but this hack spaces out the challenges level-to-level, which is very professional, much like official Nintendo levels.
• You may not have re-themed all the worlds, but nearly all the worlds you did re-theme were astonishingly creative.
• The FG effects (such as the falling leaves, the sandstorm, etc.) are very well done and unique.
• While it's unconventional in a Mario game, the Arceus easter eggs were fun to find, and a good feature in my opinion.

Negatives:
• As others have already mentioned, the 1-Tower secret exit is completely blocked off. This makes it impossible to get 100% completion, and that's a pretty big flaw since some people are going to spend hours looking for a secret exit that isn't there.
• There are several star coins and secret exits that require power-ups not found in the same level. While this was done once or twice in the original NSMB, it's not a good idea to use the concept too much, as going back to old levels just to get power-ups isn't fun, especially when you can't save until post-game.
• A flaw I also (strangely) found in MF64's hack; World 6 is a second desert world. The other world themes you replaced were fresh and original, so why on earth would you replace World 6 with another desert world? You could have kept the original mountain theme or done an awesome new theme entirely. You pretty much threw a huge opportunity down the toilet.
• It's not a huge problem, but 5-4 is nearly impossible. It's basically kaizo-esque. I had to use a mini mushroom to bypass the precisely timed jumps, and even then it still took 15+ attempts. Throwing a level that hard into the World 5 mix isn't a great idea.