Everyone talks about getting to tier 2 and running it and stuff like that but what are tiers? Also when you go to the arcade and right click on a elevator, the thing come up with like *Join party, Create Party* and whatever but there is a map to the right of that. can someone explain the map please?
Here's the wiki's explanation of tiers. Monsters act differently from tier to tier, usually becoming more difficult to fight, using different tactics and doing different kinds of damage than the previous tier. There are examples of monster tier differentiation also on the wiki.
For the map, that's the Gate Map. I wrote a short guide on my blog a while back.
Hope this helps.