The game has been hacked to remove a site lock which prevented the game from being completed.

The flat iron piece has two uses; after you use it to cut the latches which are tying the drilling machine, the flat iron piece will disappear from the inventory and the game will become unfinishable if you didn't use it before on another object. To prevent this bug from happening and be able to complete the game you need to use the flat iron piece on the latches only after using it somewhere else in the game.