This card's Level and ATK power is equal to that of the trump card of the "Ancient Gears", "Ancient Gear Golem". Even though it does not always have the piercing damage that "Ancient Gear Golem" has, it has one distinct advantage: It can be Special Summoned, while the "Golem" cannot. For this reason, at least one "Gadjiltron Dragon" should always be included in a Deck that also has "Geartown", since a powerful 3000 ATK monster will always be Summoned from your Deck if "Geartown" is destroyed.
This card is best when "Green Gadget" is Tributed because more damages are likely to be done than the other "Gadget" combos. Doing so gives this card the damage equivalent of an "Ancient Gear Golem". If it can be Tribute Summoned with both a "Green Gadget" and one of the other "Gadgets", however, this card's damage output will exceed that of "Golem".
If "Green Gadget" is Tributed, use "Limiter Removal" to do a great amount of piercing damage.
This is in most cases the best card to Special Summon with the second effect of "Geartown", due to its high ATK.
For best result, use "Magical Hats", and search 2 "Geartown" Spell Cards. When they are destroyed (which will automatically happen), Special Summon two "Ancient Gear Gadjiltron Dragons".
If this card is solely in your Deck for Special Summoning with "Geartown", this card can be used with "Trade-In" since "Geartown" can Special Summon it from the Graveyard anyway.
Destroy your own "Geartown" with "Twister". Then, since 500 LP is paid, equip this card with "Megamorph" for a 6,000 ATK monster as early as your first turn.
If there also happen to be a "Limiter Removal", a 12,000 ATK monster could be there (still as early as your first turn). This card can be equipped with "Heavy Mech Support Platform", and then activate "Limiter Removal" for a 6500 ATK. Then your Union monster will just be destroyed instead at the End Phase.
Using this card with "Fairy Meteor Crush", "Red Gadget" and "Yellow Gadget" will give this card the ability to inflict piercing battle damage and deal 1000 additional damage from the effects of the other "Gadgets".