USC Boss Rush

The USC Boss Rush is the final boss of Ultra Speed Challenge 2.5+. It contains many boss phases (six!) each based off of one facet of the personalities "beneath [the Player Active's] diamond-hard skin."

Phase 1
Objective: Survive

This boss is vs. Unikitty! This boss takes place in the Unikingdom. Unikitty explodes out of the Player Active, and begins flying around. Unikitty will choose from one of three attacks. There is a cross formation, where she will fly from the top-left and top-right of the screen diagonally to the opposite corner, a horizontal formation, where she will fly from the left to the right of the screen at a random height, and a vertical formation, where she will fly from the top to the bottom of the screen at a random column. The player can move freely in every direction here. Touching a Unikitty closes the game instantly. Surviving for one minute wins the battle. Despite only one Unikitty bursting out of the Player Active, each attack features multiple Unikitties flying around. How does she multiply? She's Unikitty.

Phase 2
Objective: Defeat

This boss is vs. a giant blue hedgehog head! This boss takes place in deep space. The head bursts out of the Player Active, the recoil of which sends the Player into a spaceship. The player can move freely in every direction while in the ship. The player can fire bullets at the head, and after 200 successful hits, the player can continue. The head has five attacks: In one, it moves to the center of the screen and extends out rotating axe blades. In another, it makes copies of Ridge Racer fall from the sky, damaging you on contact. In another, it fires homing missiles at you. In another, it fires long, awkward shots at weird angles to throw you off. In the final one, there is a moment of charging up, and then a laser fires in the middle of the screen, forcing you to move to the top or bottom. You can survive three hits in this phase, but the laser will kill you instantly.

Phase 3
Objective: Survive

This boss is vs. a plague cloud! This boss takes place in a plague-infected city. The plague cloud will follow you relentlessly, killing you on contact. The player takes on platforming controls for this phase. Every 5 seconds, the room will alternate between two platform layouts. After surviving for fifty seconds, the plague cloud will dissipate, emitting a spooky noise.

Phase 4
Objective: Defeat

This boss is vs. a green frog man! This boss takes place inside of Earth's orbit, on a piece of debris falling to Earth. The player has platforming controls for this boss. For the first phase, the green frog is within a giant green frog robot, which hovers around and fires shots that move in tricky patterns. After taking enough damage. The boss will retreat to the far right of the platform, suck in all the debris around it, and build a wall out of it, separating the player from hurting the robot. The robot's cannon will detach, as well as its eyeball. The cannon will fire more of the tricky shots from above, while the eyeball will fire rockets at the player. After the wall has taken enough damage, it will be destroyed, and after hitting the robot one more time, it will blow up. Then, the green frog man will hop out of the machine. It stands at the far right, and spits out giant circles of tricky shots in short intervals, forcing the player to jump a lot to avoid them. After the player shoots the green frog man enough times, they will win. The player has ten health points here for the whole battle, and tricky shots take away one health point each, while rockets take away two. The rockets can be destroyed if they are shot.

Phase 5
Objective: Defeat

This boss is vs. a creepy masked killer! This phase takes place in a dark room, with only a little light following the player, obscuring the room's layout. The view is top-down and the player can move in all directions. There are doors at all four sides of the room, and a pad near the center of the room. While the player stands on the pad, they will charge up power. Every so often they will hear the killer rattling at one of the doors. The player has to find out which door is rattling, and hold the door shut until the killer gives up the attack. This cycle repeats until either the player has charged up enough power to escape, or the killer manages to break into the room, which kills the player instantly.

Phase 6
Objective: Survive

This boss is vs. Red Active! This phase takes place... somewhere. The player can move freely in all directions for this phase. The player can fire bullets, but they have no known effect on the boss. The true aim is to survive. Red Active is constantly firing two streams of bullets off to the bottom left and the bottom right, trapping the player in one part of the screen. It is also constantly firing bullets in the general direction of the player. It is also acting as a gravitational force, constantly pulling the Player Active towards itself, to pull it into its bullets. When the player is hit by a bullet, the boss, and the Timer, resets. The boss appears hopeless, but after resetting by waiting out the timer three times, the Old Man appears and begins to help by messing with the Timer. The player must continue to survive by running out the Timer another five times. After those five times are over, Red Active explodes, and the game is completed!

You Win!
Objective: EAT CEREAL!

You've earned it!

Trivia

 * It is rumored that the boss phases are based off of the creators of the Speed Challenge games. This is likely just a fabrication, however, as Red Active hasn't run with that crew in over fifteen years.
 * There are no checkpoints in this boss rush, which many feel was a fantastic idea, because death does not hold a sting in this game.
 * It should be noted, however, that this is only true on Opposite Day.
 * If you enter the Contra: Hard Corps Level Select cheat code on the fourth stage, nothing happens, but you'll look pretty stupid, and probably die in the attempt.
 * The fifth phase is generally considered the best phase of the fight, while the second phase is considered the worst.
 * This is also only true on Opposite Day.