Each username can only receive the 100 credits per island once for each island. To earn any more credits would require playing the next new islands. There is a free Earth Day game in the Store that awards 50 credits. Adults may also purchase credits.
Given the limited supply of free credits, some players have created more than one username. You can have as many as you like. But credits cannot be added, swapped, or exchanged between usernames.
No, you can't be in two islands at once. But you can save on one island and go to another.
There are no levels in Poptropica. Once you beat one island you go to another and if you beat them all you can either go to the places where you can play against other people or wait for new islands to come out.
There is not a poptropica 2. But it would be awesome if it was. Once you beat poptropica then you have to wait for a new island to come out.
Once a character (username) has earned credits for all islands and the Haunted House, there are no other free credit opportunities for that username. You may create a new username, but any credits earned could not be transferred between usernames.
Once i went to one of the islands and somehow got a new player
You can't. That would defeat many of the challenges on the islands. Going to Super Power Island is a favorite way to beat ad-games because you can fly on most of them once you have your power. (see related question)
You don't need to be a member to get out and\or complete it. Once your done, move down to another island by your blimp. Early poptropica is one of the easiest islands ever made.
Wait until the next island comes out, obviously
You dock at one of the islands and once you're docked you just make your character jump off the ship.
In poptropica, go to Nabooti Islands. Once there, after a series of people talk to you, you'll recaive a map. Click it and fly the little plane to the top right of the map. There, you will find Giza.
you start moving upward from Earth, then once your in the boundry corner, start looking around, its close! (trust me I have beetin all the currant islands, from early poptropica to counterfeit)
You go into the future and talk the the future you, and she/he will give you the medal.