First, you unlock a Zim costume. Put it on. You are now able to go into Zim's house. You run into the bathroom. Dib tells you who he is and that an alien (Zim) has escaped down the toilet. You flush yourself down the toilet into Zim's Lair. Zim tells you who he is and since you are wearing your Zim costume, Zim lets you work with him and his SIR Unit, GIR. You have a human inside of a tube. You pull a lever. A brain comes into another tube. Zim tells you that you have just taken a brain out of a Poptropican. GIR detects that you are a Poptropican in disguise. So, you get kicked out of the roof and out onto Zim's front yard. Dib asks how you get in there. You choose to say "Ummm... Zim let me in". Or "I'm an Irken too". But, both ways, Dib tells you that you make it look easy. He walks away. You choose to sleep inside of Zim's mailbox. A black screen comes. Then, you wake up and go to skool with Zim and Dib. You tell the teacher you're new. She seats you in between Zim and Dib. Zim tells you to not let Dib know, but he's an alien even though Dib already knew. The bell rings. You and the other kids run to the gymnasium. The gym teacher tells the class that they're playing outside. You run to the door and open it. A girl walks by and says thanks, and that her name is Gaz, and she welcomes you to the school. You play dodgeball. You choose either Zim's team or Dib's team. Zim chooses you. You play a minigame that you have to aim your mouse near Dib's team. Then, you click. If you win, Dib tells you "Good game". You walk over to Zim. He tells you that he is going to take your brain away. You run away to Zim's Ship. You fly to Irk, Zim's planet. Zim and GIR take an escape pod. You fly to Irk and land. You find Dib and Gaz inside of the ship with you. Dib tells you that Zim crash landed back on earth. Gaz gives you the Islabd Medallion. You also get a GIR Follower. You get to keep the Zim costume. You also get Dib's shirt. Gaz gives you her Game Slave. You get to play it on any island.
Students in Zim's Class
Zim's Escape Roof
Planet Irk (rest of it blocked off by Tallest)
Dib's Shirt (and glasses if boy)
Game Slave (minigame)