The Great Perhaps

Here is my 100% Achievement guide for The Great Perhaps.

As we leave the metro station, we will end up in a carnival (Past)/Field Hospital (Future).
Go all the way to the right to see a spoiled child who has a key but wants a balloon.
Ok then...

We need two items for a clown who gives us said balloon.
First off from where you begin, just a tiny bit more to the right in the future, there is an alcohol bottle.

Run all the way to the left until you see a trailer, go in, give the clown the bottle.
Go back out and to the right, next to a hot dog stand and where superman and batman are standing (This is obvious) .
Go back to the future to pick up the helium bottle hre, go back to the clown, give it him.
He gives you balloon, you give it to little girl all the way to the right and job finally done!

Go to 10:20 to see how and where this can unlock.

Hope this helps!

When you leave the Metro, you'll phase in and out as you go right through a carnival/field hospital. When you get all the way to the right, you'll see a girl steal keys from a guard. You need to get the key from her.

She wants a balloon. Toward the right of the carnival is a train cart with a drunk clown inside. He'll give you a balloon if you give him some alcohol and a He canister. Both are the found in the field hospital phase. Take them both to the clown, get the balloon, then throw the balloon at the girl using . She will drop the key, and you'll get this achievement.