Which one is world 4 btw? The skeleton one? i wasn't sure if we were supposed to do the bottom for before moving up.
I kept going up the archstones left side to the top. So I'm in the prison world with my save point post the first boss.
So there is no real order really. The way the game is structured is that each world’s first part is at the same low difficulty, and it ramps up as you progress in each level. Yep Level 4 is the one with skeletons.
I made the mistake of getting to level 1-4 and that boss was just kicking my ass, until I realised that you need to leave him until the end as that’s the final boss. Go figure.