Hell-O @brian_selewskia this is about AG quests, so next time please search for a proper thread (or create one by yourself of course).
However, here is the solution: dont grab the key the first time! Jump over the key, you reached the door, your kittys cant pass and go back, then grab the key, you have to prepare one kitty with a "remove obstacle" outfit to go up,. the rest is easy (take a look at the level scheme).
This is better then the other games in this series that I've played. Unlike the newer games, the costumes actually have stats here, giving the game more strategy and making it less mindless. The fact that this is a platformer rather then an idle game also helps a lot in that regard. Although the only thing you can do is jump, you still have to figure out how to traverse each level, get all the chests, and get to all the enemies so you can kill them and steal their clothes(and yes, I know that sounds very wrong). Unfortunately, it's also just as repetitive as the other games. To make matters worse, there is only one music track throughout the whole game. Fish are also placed very poorly at times, being put in spots where it's impossible to collect them. (The tail end of level 19 is just one example of this.) Lastly, the worst thing about it is that(due to it's heavily repetitive nature) it wears out it's welcome long before you reach the end, and it's because of this that I can't recommend the game to anyone. It's a shame too, because I think that if the game was just half as long it would be pretty dang good overall.