High-Altitude Impact Missiles

High-Altitude Impact Missiles are a series of Missile Launchers used by the Fencer class in Earth Defense Force 2025, Earth Defense Force 4.1: The Shadow of New Despair and Earth Defense Force 5. The weapons that fire them are called High-Altitude Impact Launcher which will hereafter be shortened to HAIL.

Description
The HAIL is a back-mounted multiple launcher which fires volleys of vertically launched missiles with strong homing capabilities and moderate damage and flight speed. The missiles have a climbout period before they start to seek their targets, allowing them to be fired over obstructions. HAILs excel at long-range area suppression and engaging airborne foes, though on higher difficulties their missiles can have trouble keeping up with faster flying enemies.

Missiles from a HAIL use two-stage propulsion (like a lot of real-life infantry missile and rocket weapons) with an initial "soft launch" phase which lobs the missiles clear of the launcher and has them fall diagonally at the Fencer's sides. After a short delay their main boosters ignite and they climb to a fixed altitude above their launch location, before "nosing over" and beginning to seek their targets. It is vital to note that the missiles inherit momentum from the Fencer's movements, and will explode if they strike the ground during the soft-launch phase: walking sideways towards the side the launcher is mounted on or firing while standing on uneven ground (especially rubble) will tend to result in heavy self-damage, while launching while descending from a jump is almost always fatal.

Like most lock-on weapons in these games, the HAIL is fired by holding the fire button for the side it is mounted on, which will create a red bounding box. Symbols will appear in this for any enemy in the weapon's effective range and inside the box (it cannot lock on to friendly units), and change with a beep sound when a lock is acquired. HAILs, under normal circumstances, are limited to a single lock-on per target per launcher. Releasing the fire button will fire all currently locked missiles: the lock can be cancelled by swapping the Fencer's weapon sets if the player does not wish to fire. A lock, once achieved, will persist for a short time even if the Fencer does not keep that specific target within the bounding box.

If an Air Raider's Laser Guide Kit aim point or a Guide Beacon is within a HAIL's target bounding box, the system will preferentially lock onto it over anything else. These devices override the normal limitation of one lock per target on HAILs, and they can instead lock all their missiles onto the designated point. This allows a team to change HAILs from an area-suppression weapon into a sort of ersatz Haytal Multiple Missile system at will.

Again like most such weapons, a HAIL will become empty each time it is fired, even if the number of locks acquired is less than its total ammunition: any surplus is lost on firing. It cannot fire at all if there are no locks.

HAILs have minimal effects on the Fencer's aim speed and inertia, and none of their functions interfere with the Fencer's other weapon. If the Fencer has two launchers equipped, they can launch at the same time: locking on both together will result in both locking on to the same targets, while locking on one and then the other can be used to spread out their damage among more enemies.

Variants
"Flight time" is a measure of how long the projectile exists for after it is fired; it is deleted if it has not hit anything before this.

EDF 5
HAILs were significantly altered in EDF 5 with the most obvious addition being that they now include a jump booster rather than having no secondary function. This makes launching them a lot less risky as they can always be fired off in mid-air. As they still inherit momentum from the jump, it is important to launch in the upward part of the jump rather than while descending.

The new upgrade system allows HAILs to dramatically exceed their previous iteration in almost all areas: in particular, the lock-on speed is improved to the point it only takes slightly longer to generate 14 lock-ons than it took to generate one in the prior games, allowing for almost instantaneous volleys. In addition their reload speed is cut down and their range drastically improved, with the final variant able to shoot almost the whole diagonal distance across most maps.

The only way they do not exceed the previous game is that their damage and splash radius has been downgraded: this does have a positive side in that it is less damaging to allies if a missile goes off-course, and easier to avoid damage from near-misses.

It is worth noting that a HAIL cannot interrupt a dash boost to fire, or the firing animation of several weapons such as the Arm Hound: if the player releases the fire button for a HAIL during a point where it cannot fire, the launcher will not fire but the lock-ons will remain visible. It will then fire immediately on the locked targets the next time its fire button is pressed (not when it is released as normal).

Variants
All stats shown reflect maximum upgrades.