Why do I have to make a new game every time I want to play The Ancient Swamps or the higher levels from there? Yet when I try starting a new game on my own I usually die a few million times trying to attack those gator on my own but then other players start to join in.. How are they joining my game but I can't join anyone elses?

These people who join my games are also not on my friends list either so I don't know how they are joining my game. I would like to join other players games for these higher levels, can someone explain to me how to do this?

I've also just reached level 33 so I need to play these levels to keep gaining xp but my death count is going WAY up because I can't defeat all of these enemy's on my own.

-Ben