The Egg Hammer Fortress is the fifth boss fight for Sonic and sixth boss fight for Blaze in Sonic Rush for the Nintendo DS. On the deck of the G.U.N. battleship Huge Crisis, the heroes face off against Dr. Eggman or Eggman Nega, who return with this pendulous, ophidian machine from the Leaf Storm boss.
As usual in Sonic Rush, here both the Eggmen have the keys to this ride; Blaze fights the machine under the control of Dr. Eggman while Sonic battles Eggman Nega in the same vehicle.
This is exactly the same as the Egg Hammer Mega fought back in Leaf Storm - just given a crimson coat of paint - so many of its moves and tactics are the same. However, the fat scientists make this fight more difficult simply by being faster. The machine stays 'stunned' on the ground for significantly less time than it did in the forest level, meaning the player has to be a lot quicker if they want to land a hit.
- As in Leaf Storm, the Hammer's primary attack is a head-slam, which comes in three flavours. One, he simply smacks the ground; two, he pulls back his head and scrolls across the screen following the player until the bot snaps forward; and three, an attack not seen in the Leaf Storm boss, he slams down but rebounds and slams again twice. Each of these attacks ends with the boss' cockpit/head languishing on the deck for a split second; don't miss the opportunity to whack it when it's down.
- Taking advantage of the fact that they're fighting on a giant battleship, the robot will occasionally peel away from trying to directly splat the player and disappear into the background. Placing its head on a large button, the boss activates the ship's cannons, which proceed to strafe the player's platform with explosive shells. This attack replaces the 'rolling head' attack that was used in Leaf Storm.
After the battle, Sonic and Blaze meet for only the second time on a nearby island. Tails quizzes her about the tear in the space-time continuum, but Blaze refuses to answer any questions, insisting that the problem with the Eggmen is hers and hers alone.