Cool, I'll hop on next time.
On an unrelated note, after putting more time in, I'm seeing a lot of really good design decisions, which just underlines the impression of the series as being well-made under the skin.
1. The weapon switch & reload system. So much about this is good. The ability to interrupt and continue reload cycles (and to dual-reload by spinning the scroll wheel). The slight delay before swapping, which helps discourage lazy reactive swaps. Firing cooldowns still decreasing even when the other weapon is out; the thing that allows the fire-swap-fire cycle trick with stuff like Lysanders.
One specific example is how the multi-shot launchers interact with the Ranger's roll--namely, the roll interrupts the firing sequence, but one last rocket is fired into the ground, ragdolling and damaging the player. However, no more are fired until you stand back up, at which point the remaining rockets fire. That suggests a specific intent behind the design of the system to punish the player for poor decision-making without being totally unfair and insta-gibbing them with all of the remaining rockets.
2. Difficulty levels and allies.
There are a lot of clear inspirations in the content, but in terms of the design the closest comparison I can draw is with Soulsborne games (at least on the harder difficulty levels). It has the same sort of progression in which there are clear safe points and failure any time between them means losing everything material that you've gained. This serves the same purpose of encouraging players to, in the vernacular, git gud; the most important gains are experiential. You start to learn where all the enemies come from, which weapons are good against what, how much damage each can take to die (on any given difficulty), &c. Likewise, that element of the game creates the potential for farmable sequences, which help prevent the player from getting stuck.
The higher the difficulty, the more the value of friendly characters becomes apparent: namely, they allow you to fight in ways other than a constant fire-and-retreat cycle. A player tends to first learn this when they kill (or allow the enemy AI to kill) all of their NPC allies and then get swarmed under. Likewise, the game becomes radically easier when you have multiple players, not just because of revives, but because you can split attention or stagger your reloads. It's also why the Ranger's special ability is so powerful--in a void, the ability to heal your useless NPC cannonfodder by grabbing health sounds like it would be actively detrimental, but it's actually the sole way to prolong the duration of one of your most powerful resources, especially on higher difficulty levels when you have to danger-close them with high-powered explosives.
The nature of the difficulty also closely resembles the Soulsborne games in the sense that, while even a single trash enemy can hypothetically kill you quite easily (on Hardest or Inferno), in practical terms an experienced player can easily handle any single enemy, however powerful; the real danger is in swarms, even of the worst enemy types, because combat is oriented around the reload cycles which don't mesh well with a constant onslaught of massive numbers of targets. The very first mission is actually a quite clever git gud moment, since it's the only one where grey ants don't have their acid attack, so they all swarm and go for the bite--very, very dangerous on Inferno or Hardest if you don't have a weapon good enough to one-shot them at a rapid pace, and even somewhat if you do; as above, it also helps clever players realize early on the value of having allies on the field.