I just finished playing the hack all the way to the end, and I must say, it was definitely worth it, especially since it is hyreforgling's first SMW hack, and was quite awesome for a first hack. This is my first review, by the way. (Warning: long review.)
As you go through the game, it gets a lot more tricky. The first level was a bit easy like it should be, the second one was pretty good (except the music blocks glitched in graphics when I jumped on them), and I'll admit I fell for the P-block trap at the beginning of the third level D:
You have castle design down to a science, even though this is your first hack. Timing is everything in both of them. The first castle was more difficult than the second one, so maybe change the order of them in the final release. Now how many times did I get killed by the falling walls near the end... hmmm... These castles take much concentration to finish, and that's how a boss level should be. Excellent.
I appreciate this hack even more because you don't try to use a whole ton of ASM to make it great, but rather, push SMW's already built-in capabilities to the limit. Also, I like the GFX tweaks you made to the coins, and the little "YAY" when you earn an extra life. You also made power-ups quite rare, and lives hard to get, which add to the challenge, but it's rarely frustrating.
Don't be afraid to add custom music and more of your own graphics (since you're pretty good with drawing) in the final, and be sure to decorate the early linear levels since the first two were average. The game got pretty good after the third level, and addictive at the first castle. Everything should be relatively easy to transfer.
ASM is optional, but you don't really need it since you're familiar enough with SMW to bring out the best in it.
My rating: 8.5/10
+Tricky traps when you least expect them
+Excellent castle design
+Short, sweet levels that still test your reflexes
+Nice personal touch with the Yoshi coin - looks like a palm tree medallion and looks right-at-home with other SMW GFX
+The secrets are VERY well hidden in the ocean levels
+No overload of cheap power-ups, Yoshis, or moons, but rather BALANCED in how many there are. (in fact, I only found one feather and none of the other two)
+The title screen was well-done in my opinion.
+Difficult but not frustrating - it can test your patience, though.
-Early levels are linear, undecorated
-Second level's music blocks have glitchy GFX when you jump on them
-Bonus room colors - Yellow and blue - maybe change the yellow to something that doesn't scream.
-I think there was one blind jump, and make sure the player knows to jump up in the Not-So-Big Cliff level so they hit the teleport block and not fall to their death. Coins as a guide? ^_^
Fixing those flaws should be a piece of cake since they're minor. Take your time with the final because many of the demo ones were impressive, and I'd be surprised if you can do better than that. The first castle was an epic win. You have the right idea.