A key appears as a yellow circle with a face, the face having two eyes and a mouth, and small cheeks (the face resembling the emoticon '-'). Below its face is a curved bar, that on top of the end of the curve is a small bar the size of end curve. The curve and teeth of the key resemble the stylized T in Nitrome, only reversed.
Keys are placed in generally far off or hard to reach places in Hot Air Jr. A key is used to unlock a locked gate, which once unlocked disappears. Keys are the only objects in the Hot Air series that can be picked up, as when they are are gone close enough to, they go underneath the gondola of the Hot Air balloon.
Keys will cling to the gondola until the locked gate is reached, where once the gate is touched, the key goes into the keyhole and unlocks the gate. The negative effect of holding a key is that it adds a tremendous amount of weight to to the player, halving the speed at which they can move. Although annoying most of the time, it is useful in one situation.
On level five, a second key is found at the top of a chasm that has two mini axes positioned in a vertical line. The danger is that when going up, the player may be stabbed and killed. Once they obtain the key at the top, the increased weight from the key allows them to speed down the chasm faster, and can be used to speed past gaps created by mini axes. When Hot Air Jr collects a key, his emotion will change and looks a bit tired.
Keys in Hot Air and Hot Air 2
- Main article: Orange pads
Keys seen in Hot Air Jr serve as the successor to orange pads seen in Hot Air 2. In previous installments, orange pads essentially served the same purpose as Hot Air Jr keys. Hot Air 2 orange pads would unlock locked gates when Hot Air landed on these orange pads. The pads were often placed in hard-to-reach places in levels, and under some circumstances, orange pads may cause another action when landed on, such as causing a bullet to be fired during the Octoboss battle.
Orange pads were actually easier to use than keys. Despite orange pads' simplicity and easiness in use, they were not included in Hot Air Jr because orange pads would presumably make unlocking gates too easy, regular keys seen in Hot Air Jr adding difficulty in opening gates.