Continuity mistake: When the Good Boys tell newly-arrived Claude that the "CPR doll" is Thor's mom, the doll is wearing some type of headphones. The headphones are still on when Claude asks for a drink of water and shakes the doll's shoulder, but there are no headphones on the doll (or on the floor where the doll fell) when Claude sets the doll on the table. Also, when the doll falls, the flowers on the table fall over but are upright the next time they can be seen. Claude barely had enough time to pick up the doll, so it is doubtful that he put the flowers/vase upright. (00:32:31 - 00:34:21)
Continuity mistake: While Thor is taking "sips" at Soren's party, the girl [who may appear to be a boy at first glance] behind him (on the far left of the screen) changes position a few times. Sometimes she is standing directly next to the girl to her right (almost touching shoulders), other times she is further away, and another time she is standing behind the girl.
Continuity mistake: When Thor is crossing the highway before the mall and drops the beer bottle, there are three vehicles approaching and relatively close to him: from left to right, a blue car, a white (or gray?) car, and a red pickup truck. When Thor goes back for the beer bottle, there are different cars approaching, and they are more distant than the previous ones. There is a white truck in the far left lane and a white car in the far right lane and two vehicles further back in between. Looking behind Thor, the cars that have just passed him are not the cars that were first shown. Next, the initial three vehicles (blue car on the left, etc.) are approaching again, are close to Thor, and then crash.
Continuity mistake: When the cell phone Max is using to steer the drone hits the ground, the grass is mostly brown and dry. When Thor throws and smashes the potted flower/vase on the ground in the same area, the grass is suddenly green. (00:20:47)
Continuity mistake: At Thor's party, Max's hair (bangs) changes a few times. His bangs can be combed to the right or some strands are horizontal across his forehead. Sometimes he has a gap in his bangs on the right side and another time there is a gap between his bangs and sideburns. (01:20:13)
Continuity mistake: At the sleepover (supposedly, Wednesday night), the Good Boys are supposed to go to the skate park the next day after school, but they are there before they are in school on Thursday.
Continuity mistake: When they are trying to pop Lucas' arm back into its socket he has a ball gag in his mouth. Watch, as the depth of him sucking on the ball gag changes. Sometimes it's near the front of his mouth, sometimes he has it almost completely swallowed.
Suggested correction: I rewatched the scene three times and I don't think it is a continuity mistake. It is true that sometimes the ball is mostly outside of the lips and other times it is mostly in the mouth. But there is a pattern - out, in, out, in, out. I get the impression that the depth of the ball in Lucas' mouth correlates with his breathing (inhaling or exhaling) and/or varies with his arm being pulled by Max and Thor. The ball goes lower in his mouth when Max and Thor start yanking.