Setting Sun

Setting Sun is the fourth mission in Earth Defense Force 2025 and Earth Defense Force 4.1: The Shadow of New Despair. It is the first to introduce the new Retiarius enemy.

Objective
2025: We've lost communication with the Wing Diver team. Head to their last location and support the Wing Divers.

4.1: We've lost communication with the Wing Diver team. Head to their last known location and support them as needed.

Storyline
The giant insects are clearly on the ball and have discovered the key weakness of the Wing Divers is their complete inability to look where they are going, resulting in Wing Diver Unit 4 becoming trapped in enormous, obvious webs created by spiders the size of a football field.

Ignoring this radical new development in the field of stupidity, HQ orders Storm Team and the Rangers to assist the Wing Divers and destroy the new giant insects. Ohara is baffled by this new development, wondering if it means that the giant insects knew what the EDF were planning, while HQ, clearly trying to out-confusing him, grumbles that the "Ravager technology" has evolved beyond the Wing Divers.

As the last Retiarius dies, Ohara, well, um...look, we'll just leave it here and let you figure it out.

"Does this mean that the progress of the giant insects exceeds human wisdom? Progress faster than science is impossible! But..."

4.1 Changes
Aside from being able to cause a Retiarius to let go without needing to do enough damage to kill it, no changes.

Enemies
Both versions: 

Retiarius x 8 with webs (all spawned at level start)

Both Versions
This mission starts in the park area of City 2 and goes into the square with the two largest skyscrapers. Many of the buildings in this mission have Retiarius webs attached to them; any such building is rendered indestructible.

Setting Sun is a very easy mission even on Inferno as long as the player knows what Retiarii actually do. The Retiarius' only attack is to spit a series of thick silk threads that are thrown in an arc; they can do this through buildings. If a player character touches a thread at any time before it disappears they will become trapped, taking damage-over-time every second or so (increasing to multiple times per second on higher difficulties) and being pulled in towards the spider. A trapping strand will flash red, and it is possible to be trapped by a thread that has already caught something else. There are only two ways to escape being trapped in 2025: kill the spider, or get fully pulled in, in which case the Retiarius will drop the player character into their web.

This is not an improvement, since the only way to escape a web is to destroy that, the web is much tougher, and it also deals damage over time. Jumping or walking into a web will also lead to becoming trapped, though the securing strands are not part of the web's collision or hitbox and will not trap characters (or take damage). The Retiarius will also sometimes decide to shoot a character in its web at point-blank range, dealing far more damage than usual.

Since the mission only includes a few tough enemies that attack at long range, it is advisable to bring a sniper rifle, rocket launcher or similar. Because most of the enemies are high up, the Air Raider's default Gigantus tank is practically useless except against the first two Retiarii; if the player has started on hard and has unlocked an Epsilon Armored Railgun they should use that instead, though hitting the fourth Retiarius, high up between two buildings on the right, is very hard even with this.

NPC Wing Divers are trapped in most of the Retiarius webs and can be freed and recruited if the webs are destroyed; if not, they will eventually be killed by either the Retiarii or damage-over-time from the webs themselves. The webs are much tougher than the Retiarii and take a long time to bring down with starting weapons.

The Retiarii will mostly concern themselves with saving the city from rampaging civilians until they are aggro'd, whereupon their attention will be almost exclusively on the character that wronged them. It is therefore a good idea to take them on one at a time. Destroying their webs will drop them to the ground and make them easier to target, though it takes some time.

There is a rather annoying zoom-in on a trapped Wing Diver at the start of the mission that does not pause gameplay; this can result in the player being hit by a Retiarius while they cannot see their character. Luckily, it is possible to disable this and other effects like it by switching "camera effects" to "off" in the option menu.

As in the previous mission, while the player is told to save the Wing Divers, there is no requirement to do so and no penalty if they all die before the mission ends.