Marathon is doing some really worthwhile things since I've last played an extraction shooter. I haven't played Arc Raiders so I wouldn't know if that game has done things similarly. My last extraction shooter was Tarkov (and that was years ago), so with that in mind:
Narrative and Lore as Reward in a Competitive Shooter
I think the biggest draw for me is the narrative to be uncovered by exploring the colony. Drip fed as it may be the bits of lore to read and listen through are interesting. Even if I don't extract with much in the way of gear, I can usually find a piece of rare salvage like the Drinkable Cheeseburger and progress that story line. And even if I don't extract at all, I'm having conversations with faction leaders and uncovering more interesting reveals with them (like what actually happened to all these colonists). The pace of the story is slow, but not slow enough that it doesn't still feel rewarding. I'm still getting regular cutscenes and developments in the story close to what I'd get in a singleplayer game.
Do the cutscenes work in a multiplayer setting? Unless you're solo-queuing you've probably got a team waiting for you to move your ass up and do another run. I think the intention, and what I've been doing, is to do runs with your friends progressing all the contracts you can and then holding off on claiming those contracts until after you're done for the night. In either case you get to wind down after a bunch of matches or have some reading material while you wait for your friends to hop into the lobby. You also get a bunch of gear which gets into my next point...
Forgiving Means Fair (and Fun) or How to Not Punt Your Newbies
Getting supplies for leveling up your factions and completing your contracts really helps give you a cushion after getting absolutely trashed by other players in the match because now you've got some gear to experiment and build with. Having skill be a hard barrier from from character building (in a game about the loot) just isn't fun when you're trying to get to grips with the game. I hope people see how this helps onboard new players to actually maintain a functioning player base. This is also the major reason why I, not normally an extraction shooter fan, can really jive with Marathon.
Getting generous rewards for just playing the game also offsets gear fear, where you're stashing everything away that you like instead of playing with it, and helps the game economy as a whole. It doesn't feel as good to kill a team of sponsored kits (the free loadouts) as it does to face a team with a fighting chance. It doesn't feel good to be stuck dying with sponsored kits either. Ideally, there should be some good wiggle room so each match feels like a curious poke at the multiplayer sandbox.
The runs feel like a sandbox because of the added influx of loot in the pool. I don't know if I'm going to run into a team with purple, blue, or green gear or what types of weapons and ordinances I'll be playing against. I learn I can expect to see anything in play. That makes fights and looting consistently exciting.
Whether you're good or bad at the game you get to see all the content. You'll certainly be rewarded with faster progression by winning with the mechanics or with a good strategy (or lucking into some good loot or a good situation), but this just adds depth to the experience, not a barrier to entry.
I like that this isn't a zero sum game. People willing to try weird strategies or ballsy plays. One team I closed in on had put so many claymores in the building that I felt like I was back to playing R6 Siege, disarming defenses while watching points of entry, while watching out for another team trying the same thing. And even if I die to some bullshit, "Hey at least I progressed my contract." This keeps the maps refreshing because players are interacting more. Speaking of the maps...
The Multiplayer Arena as Vehicle for Environmental Storytelling
A quick tangent: Not every immersive sim is that open ended. I play Dishonored and there's really two strategies, loud or quiet. And both feel boring because both are easy. After your first two playthroughs of Dishonored you quickly fall into optimal strategies with no reason to step out of them. Without any danger the world feels hollow and unreal. And what a disservice it is to that world to feel rather than immersed in it as totally above it all. This is by no means what most people's experience with Dishonored is, difficulty is subjective after all, but it is mine.
I bring all this up to say that, unlike Dishonored, here in Marathon there are actually enough varieties in approach to warrant re-exploration and plenty of incentive with progression between matches being tied to engaging with objectives in that world. I feel a bit closer to what Deathloop was trying to do, make a setting for a game of death that I slowly get to unravel and understand the mystery of.
I think this promise is the only thing that I feel hasn't quite come fully together. It doesn't feel too dissonant to uncover the details of the colony in between runs from a codex. I figure if I was in that world as a runner I'd only really have safety to do it in between runs anyway. But there is a disconnect there to where the stories being told of the location are over here and the actual location is over there without the two properly ever properly getting to meet.
It helps this is a game about scavenging. Factions will request certain materials to upgrade them, which means you do have to pay closer attention to what you're looting and where you're going to loot. It makes some intuitive sense too. Where do I get bio-samples? Go to the labs or agricultural buildings where they were growing shit. Where do I find the secret logs or evidence of the conspiracy? Go check those locked rooms that require keys or complicated steps to enter.
I wish there was a bit more to make each location identifiable and unique. Each location location looks amazing but it's all too cohesive of a landscape. Maybe that'd go against the corporate dystopia the story is going for or might make the places harder to move through, but I don't think it'd take a lot to go a long way. It feels a little too much like this colony wasn't ever lived in before it was abandoned. I'd like some trace of the human element to the interiors closer to Prey, something unmistakably human among the remains. I feel like what stories I'm chasing are less echoes of the past and more like echoes of echoes. Maybe the UESC are just a bit too good at cleaning up the evidence? That seems like too much of a stretch to me.
All to say, while all the pieces are here to do something really amazing where the narrative is firing on all cylinders with the gameplay, it just isn't quite there. Maybe it'll get closer with future seasons or matches creating a context on top of the world. But I think the only way I'm going to really cross that gap at this point is to put a lot more work to tie the pieces together. Take screenshots to tie a place to the fragments I find in the codex. But at that point I'm just doing a lore channel.
I hope I've painted a clearer picture as to why I love this game, why it might be popping off with some of y'all who aren't normally into this kind of game. I do think narrative and progression are doing a lot of work to make a fun game here. The game has good style and execution where it counts, in the gunplay and map-design. I just want a bit more from a shooter if it's going to be something I focus on, and for my complaints, I think Marathon strikes the right balance. This won't be the last I gush about this game, but it's probably the last I'm doing here for a while.