spoilers!!!!!!!!!!!
lvl 15: you have to flip the pattern sideways first, then if you pick out only one instance of the repeating symbols youll realize they spell out something (capitalization matters)
lvl 19: idk unfortunately
lvl 20: you have to write a word in the instructions the amount of times it takes to kill a cat, no spaces
lvl 24: level -55 is blank, like your answer
lvl 25: the place is called the ______ triangle, famous for ships sinking and other phenomena.
lvl 27-30: idk :(