The Challenge is a red-coloured level. It introduces the Spider gamemode with a entire middle part in it.
WARNING: SPOILERS AHEAD!
One of the many hints The Keymaster says is this:
- Want to hear a secret?
- Just don't tell RubRub
- I am building my own level
- I call it "The Challenge"
- Hope it gets featured
- But probably not...
- RubRub will never notice me
If you type in The Challenge, it will become playable for 200 diamonds. The Keymaster says “My level? You want to try it!?”. After getting the right amount and being beaten for the first time, he will say this:
- My level... You beat it?
- I guess I underestimated you. It will not happen again.
- ... Why are you still here?
- Ah of course, you want a prize.
- RubRub always gives prizes.
- Uhm... Not sure what to...
- Oh I know!
- I left an old chest down in the basement.
- You can have that as a reward.
- Take the door on the right, I will open it for you.
- Grab the chest and come back... DONT TOUCH ANYTHING!
Then click on the door on the right. There is a orange chest in there with a cube for you. After opening it and you don’t come back. Two glowing eyes appear. Soon this is said by whoever it is:
- Well, well, well. What do we have here?
- You look like someone who is interested in a deal...
- Help me get out of here, and I will make it worth your while.
- See those locks over there? You will need to unlock them.
- RubRub locked me in here, for no reason.
- He said there would be chicken.
- There was no chicken...
- I cannot stay here any longer. You must find a way to release me.
You may notice the three locks, clicking on the orange and blue ones, he will say “You cannot get this key in Geometry Dash World, yet.”. However, clicking by green one will come up with:
- They tried to hide it from me, but I have my spies.
- The second key is locked away in a secret chest.
- Unlock 50 secret chests to claim the key.
Sounds interesting, huh? Anyway, do that in the Treasure Room and the first special chest is now available after opening 50 of them. It includes a ball and the green chest. Go back and click on it again. It will disappear and he will say this:
- The key, you found it?
- Excellent, only two locks left.
If you did everything here in World and NOT the full version , you finished the After-Challenge challenge. You can still play the level if you want.