I want to make a game where you survive cars going down a hill and hitting you but it is impossible to do because this game will not put my bricks together and it falls apart please help

take glue and glue it together

Children positions are relative to their parents so if you make every part of the car anchored except for 1 "base" part you can make the impression that the car is welded together but it unanchored because the anchored parts will follow the unanchored part because again, children positions are relative to their parents and that is intentional as Polytoria doesn't have welds but this is a way around that setback. Good luck on your game!