I feel like you could lock yourself out from a class (the witch seems like one). However I'm not too sure exactly. Btw the game should take a while to beat. Money doesn't come by easily and the game is actual quite difficult. Also what I just learned is DO NOT go to dungeons you can't beat. You can practically go anywhere on the map however you LOSE money when you die. I'm dirt poor from dying so many times in a row. I believe it's a percentage so the more you have the more you lose.