With the game engine you will need to know some Python coding. You can do a decent amount with some of the visual blocks they offer, but a knowledge of Python would help you to get deeper into it. (it would also make it easier for you to develop your own UI tools) I'm not sure what you mean by a 2D dungeon? Would that be…
like a zelda game and I have some python and java knowledge, but really not much^^ The question is wether it makes sence to use blender for it and is it possible to make it in 2D?