Clockwork tunnels, mechanized mile right before the clockworks and shop, gate with the new boss.
This level contains a room that is impossible to complete alone. 4 levers, 3 reachable at the start, last one after turning a level.
Two levels are supposed to open gate with a button that opens a treasure room (1 T.box, 2 rooms in total).
The thing is: if I open a gate to either button, that same lever closes the path with another gate. If I open the path, it immediately locks button.
If there is at least 1 more player in my team, its possible to complete this room. If there are no more players ("go solo, invite only"), treasures will remain locked.
And here I thought all levels were built to be complete-able solo, without extra players...
Don't get me wrong: the level is complete-able. But treasures will remain locked. Its as if part of the level is floating away in unreachable space.
Every encounter and puzzle currently in Spiral Knights is soloable. Take a minute to look around the next time you see this room and you should be able to figure it out. Also in the future please submit a bug report in game by pressing F2 when you encounter something you think is broken. That will provide us with more info that helps us troubleshoot your problem. Good luck!
Hint: Monsters can sometimes be helpful.