You have to ask G before you can have the key
In G's droor
you get a key from G and go up stairs to break the big magnifine up on the roof
you get it from a draw that G will open for you after you electric shock the macanical box
You need to specify your question.There are no "keys" in mission 2.If you are referring to the mission where you find missing coins,than its in G's drawer.
On Mission 6, the black puffle releases you from the cage. You don't need a key.
for the cobinationtype in key
it is the first one
the code is key
key. If you didn't notice, Gary puts key in these (")
G will give you
key
Go to G in Mission 3, talk to G and click the drawer. Get the gold key one.