VGFacts

Transformers (2004) as you know is a game based off of Transformers: Armada. As such, it features Mini-cons heavily, small Transformers that combine with larger ones to make the latter more powerful. The Decepticon Cyclonus (An attack Helicopter) has his signature Mini-con, Crumplezone, attached to him in Vehicle Mode at all times but the Mini-Con is nowhere to be found outside of his Vehicle Mode. This is unusual as, like in the game ,toyline, show, etc. with other mini-cons, Crumplezone should appear next to Cyclonus or along side him when he Transforms into Robot Mode, but he doesn't. The part of Cyclonus' helicopter mode that Crumplezone attaches to is his cockpit, essentially making Cyclonus go from a Flat-fronted Heli to a long-fronted Heli if that makes sense. The flat cockpit (NOT Crumplezone's longer one) can been seen in Cyclonus' Robot mode as it forms his chest. Thus, it's possible they did all of this just to make Cyclonus look more "intimidating" and cooler-looking in Vehicle Mode.

Here is footage of the boss battle in which Crumplezone (light blue cockpit) can be seen attached:

Transformers (PS2): Cyclonus Boss Fight - YouTube

Here is a picture from the show showing Cyclonus flat-fronted without Crumplezone attached:



Here is Hasbro's toy featuring the Crumplezone attachment feature:



Here is Crumplezone the troublesome Mini-Con himself:



(Notice the legs of his Robot Mode)