I have completed every level and every quest (that I know of) in the game, but I am only at 98.7% complete.
I have found all 8 Eggos, all 8 VHS tapes, all 12 garden gnomes, and all 40 heart pieces. I've unlocked Eleven and watched the movie in the Hawk Theater.
In my inventory, I have 3 backpacks, an aluminum bat, a D-cell flashlight, a Canadian tuxedo, a 20-sided die, a spiked club, and a Ghostbusters lunchbox. I also have the hazmat suit, dynamite, flowers, and the key, but those are all required to complete the game anyway. There are no quest items remaining and I've talked to everyone in the game.
What am I missing?
I'm playing on hard if that makes a difference.