wow congrats, 100% is an amazing accomplishment!
i put a lot of work into the credits, i felt like if anyone was willing to put in the hours to finish the game i wanted to have something special for them. I'm glad it made you smile, and I hope someday I can make another game to make you smile again :D
Yes, if you buy enough mystery boxes you can get an item from them -- it is an electric version of the vibrator toy, with a special button to zap the pokemon. (they do not like it...)
frankly it is not worth the grind, and it does not count towards your completion percent! but if you come back to the game and do puzzles every once in awhile, maybe some day you can unlock it. you have to open about 8-10 mystery boxes, i think.
