This was a very ambitious game and very interesting premise. Pokemon meets Stardew Valley meets Trick or Treating. The Treat minigame was fun, the Trick one, was definitely a trick. The music was creepy and catchy - good tone. You definitely put a lot of work into this.
When I played the Treat minigame, even when I caught chocolate, I never got it at the end. I also seemed to get less candy than I caught. After I upgraded the large mansion in the upper-left-hand corner of the game and tried to Trick-or-Treat there, the game hung on the Treat loading screen and I had to reload the page. I also didn't seem to get any candy from my monsters, even the Pumpkin King.
You have the bones of a really promising game here.