Just prior to 13 minutes into the movie when the Bean Bag Boys are eating in the cafeteria the students at the table behind them disappear than reappear several times during the conversation.
Towards the end in the montage which Thor sings over, Max cries in the skate park after Taylor breaks up with him but shortly afterwards find out that he has been grounded for a month between the kissing party and the Bean Bag Boys catching up at the party following the play.
The Bean Bag Boys play Ascension: Deckbuilding Game. In order to make fast cash, they attempt to sell a rare and valuable card that they purchased a few years earlier in a random pack. Ascension does not sell random packs. It is made of a base game and preset expansion decks, thus making it impossible for rare cards to exist (outside of promos which are still not available in random packs), making this plot point impossible. Magic: The Gathering, however, is purchased by buying blind, random decks that may or may not include rare cards.
When Max pulls out and repeatedly fires the paintball gun, it appears to not have an air supply, so it could not work. In fact, it has a (small) Powerlet or 90 g single-use cartridge attached by an adapter to the tank port. It also has a small hopper, so it could work with that gas and paintball supply just barely having inflicted the mayhem shown, but probably not much more before it ran out of one or the other set of supplies.
(at 00:56:40) A drone box is very light and obviously empty.