Lock-On Missile

The Lock-On Missile (ロックオンミサイル発射), also known as Homing Missile Launch (ガン発射) or Homing Missile, is an attack used by Dr. Eggman, EggRobo, E-102 Gamma and Miles "Tails" Prower. It first appeared in Sonic R, and have since reappeared in Sonic Adventure, Sonic Adventure DX: Director's Cut, Sonic Adventure 2 and Sonic Adventure 2: Battle. When performing this attack, the user shoots missiles at a marked target.

Description
When using the Lock-On Missile, the users use their weapon equipment to mark and lock onto a target with a guiding system before firing a missile at the target. The missile will then from there automatically follow the target until it hits it. For those with more technological advanced equipment, the users can fire several missiles in rapid succession to multiple targets.

In gameplay, the Lock-On Missile is used by the player to attack enemies/opponents in the game that they have marked previously from afar with missiles. Regardless from which angle the Lock-On Missile is used, the missiles launched from the attack will automatically home onto the targets until they hit, either causing damage to or destroying the target.

Sonic R
The Lock-On Missile first appeared in Sonic R, where it was named Homing Missile. In this game, it is one of the actions Dr. Robotnik and EggRobo can perform during a race. Here, Dr. Robotnik uses his Eggmobile's weapon equipment to perform the Homing Missile, while EggRobo uses its standard hand weapon.

In gameplay, the Homing Missile is used to attack other characters during a race. For each usage of the Homing Missile, the player has to pay 10 Rings, with a brief recharge period between each shot. To use the Homing Missile, the player first has to let a green reticle appear on the screen and let it lock onto a nearby racer. Then, to fire the missile, the player has to press the Jump button. When an opponent is hit by the Homing Missile, it will greatly slow him/her down. Also, if the targeted character is wearing a shield (namely either a Lightning Shield or a Water Shield), the Homing Missile will eliminate the shield.

Sonic Adventure and Sonic Adventure DX: Director's Cut
In Sonic Adventure and its remake, Sonic Adventure DX: Director's Cut, the Lock-On Missile is used by E-102 Gamma, where it goes by the name Homing Missile Launch. Here, Gamma uses his machine gun to perform the Homing Missile, with the attack being a part of his standard weapon systems.

In gameplay, the Homing Missile is used to attack the targets marked by Gamma's Laser Gun. To use the Homing Missile, the player has to press the B/X Button after marking a target with Laser Gun, where Gamma will rapidly shoot enough energy missiles to hit all marked targets, which will then either destroy or damage them. However, the marking from the Laser Gun only lasts for a short while, so if the player waits with launching the Homing Missiles for too long, all marked targets will disappear and the player would have to remark the enemies.

By obtaining the upgrade Laser Blaster, the Homing Missile gains a larger attack radius by creating a large explosion upon the missile's contact with the enemy, allowing it to damage enemies close to the targets. After obtain the Laser Blaster, Gamma's energy missiles change color from yellow to light blue.

Sonic Adventure 2 and Sonic Adventure 2: Battle
In Sonic Adventure 2 and Sonic Adventure 2: Battle, the Lock-On Missile is used by Tails and Dr. Eggman. Here, Tails and Eggman use the Lock-On Missile as a part of the weapon arsenal onboard the Cyclone and the Egg Walker respectively. On Tails' Cyclone, the Lock-On Missiles are fired from the cannon located on the rear, and on Eggman's Egg Walker, the Lock-On Missiles are fired from the cannon on the left side of the cockpit.

Like in Sonic Adventure and Sonic Adventure DX: Director's Cut, the Lock-On Missle is used to attack the targets marked by the Tails/Eggman's Lock-on, with the Lock-On Missile's mechanics being the same as those games. To use the Lock-On Missile, the player has to press the /Button after marking a target with Laser Gun.

Also like Sonic Adventure and Sonic Adventure DX: Director's Cut, the player can obtain the upgrade Laser Blaster for larger attack radius when the Lock-On Missile impacts the targets. When Tails obtain the Laser Blaster, his Lock-On Missiles changes color from yellow to blue, and when Eggman obtain the Laser Blaster, his Lock-On Missiles changes color from yellow to green.

In Sonic Adventure 2: Battle, the Lock-On can target enemies on an much faster rate due to the improved game engine.

Trivia

 * In Sonic Adventure, Gamma's missiles were very fast and hit an enemy within a matter of seconds. In Sonic Adventure 2, Tails and Eggman's missiles have varying speeds depending on where they are.
 * In the normal Stage Levels, Tails and Eggman's missiles move very fast towards the enemies, but in the Boss Fights against each other, the missiles move considerably slower, so that they can be avoided easier.
 * Also in the Stage levels, the missiles never miss, but in the Boss Fights and 2-Player mode, they are not as accurate and may miss the intended target.