Depth Crawler

The Depth Crawler is a vehicle designed for underground combat that the Air Raider can call on in Earth Defense Force 4.1: The Shadow of New Despair and Earth Defense Force 5.

Description
The Depth Crawler is a single-seat, four-legged machine equipped with two large cannons and a smaller Gatling gun in a limited-traverse mount under the cockpit. It is an agile vehicle capable of adhering to any surface, dramatically increasing the mobility of the Air Raider.

The Depth Crawler is also able to jump and execute a short slide-dodge, handling somewhat like a much weightier Fencer with no cancelling options. If the vehicle encounters another surface while jumping it will stick to it, and can jump from any angle.

The Depth Crawler is also equipped with powerful headlights that provide far better illumination in the now-dark tunnel missions than the helmet lamp of a soldier.

There are a variety of different Depth Crawler weapon loadouts suitable for various situations, though all of those situations have to taken in light of the fact that it is made of spit and tissue paper.

Deploying a new Depth Crawler underground will summon it instantly on the exact spot where the grenade landed; it simply appears magically in a puff of smoke. If it is requested above ground, it will be delivered by container in the usual manner.

Strategy
The Depth Crawler is a fragile and rather jittery vehicle that is fairly difficult to use effectively. Even the highest-level versions have just 3,750 health, not much more than a top-level SDL1; at higher difficulties, it will be quite likely that the Air Raider has more health than their own machine does. This is not helped at all by the Depth Crawler's large hitbox.

The Depth Crawler is fairly fast, comfortably outpacing a rolling character but no match for a Wing Diver or dash-cancelling Fencer. It also "straferuns," moving faster when walking diagonally than it does when walking in one direction.

The main gimmick of the Depth Crawler is the vehicle's ability to climb on walls. The main problem with the Depth Crawler is that nobody told the camera this, and while it is fine with tilting up or down, it will stay parallel to the ground if the Depth Crawler moves onto a wall sideways. The Depth's Crawler's aiming controls are relative to the turret's left and right and up and down rather than the current camera position, so while it is on a ceiling they will appear to be reversed. Getting out of a Depth Crawler while it is on a wall or ceiling will mean it stays there, generally making it impossible to reenter. It can occasionally also result in glitching through the wall, and so is not a good idea.

The vehicle is still extra health in tunnel missions and it can be effective if used along with the anti-swarming methods a 2025 Air Raider would have to use in a tunnel mission anyway, ie the use of Bunker forcefield generators to shut off tunnels and ZE-Guns to assist in thinning out enemies. The vehicle's turret rotation is perhaps a little too fast and it can be difficult to draw a bead on a specific target. Cannon-equipped Depth Crawlers have piercing main guns which can hit multiple enemies at once, which can be useful against swarms; the main Compact Cannon / Burst Cannon works like the Revolver Cannon of a BM03 Vegalta, though the non-burst version fires painfully slowly.

Like most flame weapons, the Incinerator mounted on some Depth Crawlers will always fire out to its maximum range, damaging anything it contacts along the way and often hitting the same target multiple times for much greater damage than its stats would imply. It is still one of the weakest vehicle-mounted flamethrowers in the game, though; just one of a level 45 BM03 Vegalta Fireghost's two Combat Burners has greater damage output than the level 52 Depth Crawler's Incinerator, and the Depth Crawler also has the lowest ammunition for any such weapon, only able to fire for 15 seconds before running out of ammunition. Interestingly, the Incinerator produces the "Type A" flames only otherwise created by the Ranger's Flamethrower weapons, which have an additional ability to penetrate a Shield Bearer's screen and still damage the Shield Bearer itself.

The Heavy Shotguns look awful on the vehicle's stat card since the card fails to note the number of projectiles is 40: the damage is still fairly mediocre, with a shot from the level 52 Depth Crawler S Range Custom's shotgun dealing 70 less damage than a shot from the Ranger's level 41 Buffalo G4.

The Depth Crawler's Sniper Cannons are powerful, with the L Range Custom's close to the performance of the Ranger's top-level Hercules sniper rifle, though nothing compared to the raw firepower of an Epsilon Armored Railgun. They can be useful in dealing with middle-tier enemies at long range, and the Depth Crawler is good at getting to vantage points to make use of them in above-ground missions.

The underslung Gatling Gun handles like a miniature version of the bow machine gun of an E651 Titan, though the Depth Crawler's has a limited ability to pivot up and down rather than being totally fixed. It does not have the range of fire of the vehicle's mounted guns, which can aim almost straight up, and has a short spin-up time of a second or so before it starts firing. It is actually extremely powerful and probably the Depth Crawler's best weapon, with the two top-level Depth Crawler IV variants' FK200s doing 20 more damage than the Titan M3's bow machine gun per shot with the same rate of fire; this is also a lot more powerful than the Ranger's top-level AF100 assault rifle, and the same as the guns of an EF24 Bazelart Powered.

A Depth Crawler can also be useful for an Air Raider who is acting as a spotter for a Fencer, since it will allow them to reach building tops without having the startup time and weird hot-air-balloon handling of a helicopter, though it has its own handling quirks to contend with instead.

While it might seem difficult to place turrets or posts on the vehicle due to its height, the top of the Depth Crawler is actually easy to access by jumping on one of the pivots at the base of each leg, then on to the roof. Standing at the back of the cockpit will allow turrets to be placed on the front, and since they cannot hit the Depth Crawler here unless the guns are lifted, they are actually fairly effective and even ZE-Launchers can be used in this way.

Versions
All Depth Crawlers have a crew capacity of 1 and require 2,000 credits to drop. Vehicles marked (DLC) are DLC-only.

* Note that while the Rapid Bazooka's stated range figure is 120m, the projectiles are never destroyed and it can actually fire the complete diagonal distance across any map.

Trivia

 * The Depth Crawler's usual guns are Oerlikon KDA autocannons, based on the guns of the German Flakpanzer Gepard.
 * Porters finds the weapon baffling. Her skeptical deployment calls can only be heard if it is used above ground.
 * The PC keyboard command menu calls it a "Depth Crower."