Quote from Yoshiquest
So, I haven't tried updating the mod yet, but I wanted to post this before I forget AGAIN.
Simply put, I finally figured out what the lucky (or miracle) mallet does.
Basically, when you shoot any bullets with this mod, and if you use the mallet while they are still in the air, it will cause them to grow. Best example is to shoot a bullet, use sakuya's pocket watch to freeze it, and then use the mallet before unfreezing it.
Now if you'll excuse me, I'm going to try updating the mod now.
EDIT: Ok, I installed it successfully. And you guys were right: You must update java in order to install this (by that I mean use java 7 instead of java 6).
now if only we could get the mallet in survival mode