Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.
Based on some minute details with each character's ending dialog and selection animation it can be assumed that the ragtag bunch of misfits you end up unlocking has some reason for being on the UES Contact Light in the first place. For example, the Commando, Enforcer, Engineer, Sniper, and Mercenary all seem to be wearing the same uniform which doesn't seem like much of a relation until you realize that their selection animations all seem to be more confident than everyone else. In addition, those classes are packing much more combat oriented weaponry than the other five. It can be lightly assumed that they are all part of the same security detail that would be on the UES Contact Light. In addition, each of their ending quotes implies that they aren't exactly sane or human anymore.
Why would they need that kind of security for what is for all intents and purposes Space UPS? People like the Bandit. One of the enemy logs, specifically for the mechanical spider, mentions that that particular enemy is employed by pirates to filch some of the cargo off of transport vessels. Given that the Bandit's suit is of a different make than the other classes(The helmet looks like a gas mask instead of a glass bulb helmet.) And the fact that he's wearing a hat and duster over it imply that he's no military type, though the fact that he air pumps his gun in his selection animation makes it clear that he's no stranger to combat. His ending quote implies that while he did make off with an impressive haul, everyone on the ship dying in a catastrophic spaceship crash probably wasn't part of the plan.
The Huntress and Miner were likely just normal people hitching a ride on the ship. The Huntress being something of a sport shooter and the Miner being... well, a miner. The Huntress's selection animation has her nervously look around at the other survivors, implying inexperience with impromptu crash landings and her whole gameplay gimmick is kiting and running away from enemies. While running is something all normal people would do given the situation, being able to shoot a bow on the move is exceptionally difficult to do for a beginning archer. In contrast, the Miner's gameplay revolves around viciously giving every giant lizard alien a pickaxe lobotomy and moving around very very fast, something that a person crazy enough to dual wield digging implements and know how to use them ought to do. In addition, their endings are something of an antithesis to each other. The Huntress's implies that she's been permanently scarred by the ordeal, while the Miner simply hasn't come down from his adrenaline high.
The Loader's case is simple enough, as he's someone you'd actually expect to be at a cargo ship, and his heavy-lifting gauntlets would make sense as well, considering the sheer amounts of cargo on the ship.
Acrid was simply a lab experiment that survived the crash(You first find him in his cage.) And given what all his skills do, could be reasonably assumed to be a bio-weapon of sorts. This is reflected in his ending quote, stating that all he wants is to be left alone.
HAN-D Was simply the UES Contact Light's janitor robot, and CHEF its, well, chef.
- Alternatively, Some survivors were actually found on the planet : Namely (maybe) Acrid and the Miner. The miner was part of the UES presence on the planet. He just got caught in Providence's attack of the Contact Light.
The way that Acrid, the Miner and HAN-D are unlocked confirm that more than one crewman survives the crash even if you're playing solo. Acrid dies in every run except his own; he either suffocates in his box or is killed by another survivor, but HAN-D and the Miner survive in their own runs and whatever runs they're rescued in.
The Commando is a pragmatist, perhaps a result of a less-than-spotless military career. His endquote reveals that he leaves "with every*thing* but his humanity," implying he took the rest of the haul (and everyone else's share) and waited for no one, leaving every*one* else stranded. The Bandit is implied to have done the same, even if he wasn't happy about it.
Whether because of good nature or because s/he sees the value of a good spotter, the Sniper is a team player. If the a non-Sniper player earns "Telescoping Sight," they make contact with the Sniper who provides distant fire support; that's why the killing projectile doesn't seem to come from your weapon or character at all, but a plane perpendicular to the player's path. Note that Sniper's endquote says "they" left; while it could merely be gender ambiguity, it implies s/he wasn't working alone, and made sure the partner got on the ship, too. If the Sniper player has it, s/he's working with the Huntress.
The Miner owes his life to some other character, as he can't get past the Direseeker in the Magma Barracks without help. This makes sense, as based on his weapons and abilities - repurposed mining tools all - he is not a combatant. Having a companion during his time on the planet may be why he alone of the humans was not completely traumatized by the experience (based on his endquote). It's possible the Sniper is his rescuer, but it could theoretically be anyone, even Acrid. If it's the Commando, he's doomed anyway.
The Huntress is possibly a member of an alien species or offworld human culture with advanced tech but a spiritual tradition that is reflected in her weapons, title and abilities. The end-line about "her soul remaining on the planet" may indicate she was profoundly touched by encountering Providence in a way others were not, as an expression of Gaia's Vengeance. As mentioned above, she survives in any Sniper run that includes the Telescoping Sight.
The Loader's endquote is ambiguous, but it mentions "rebuilding his life," implying he may have been very close to someone on the ship who was killed. It's possible, however, that he simply has no future prospects, no longer being employed on the Contact Light, and being considered with suspicion by other vessels as a result of the incident (a nod to Ellen Ripley in Alien).
The fate of the survivors in a Mercenary or Enforcer run are left totally ambiguous, though it's implied that the Mercenary of all people is the most wracked with guilt.
- Alternatively, the music could be Providence singing. This might be why the music goes from intense to sad near the end of the game - it's in mourning for everyone you killed.
Providence is a literal immortal, with its "soul" creating its physical form. As such, the only thing that actually happens when you kill it is that you fracture the soul a bit, temporarily stopping it from physically manifesting.
What happens then? Well, based off of the extremely dark ending quotes (and how a good deal of them mention that the survivors feel like a piece of them is left behind on the planet), killing Providence may actually fracture your soul as well. The new Providence is then constructed from the former fragments of its self and the piece of its killers soul.
Providence isn't a single entity. Providence is a cycle made out of everyone who has ever "succeeded" at killing it.
- Jossed by a devblog post confirming Providence won't be in the sequel due to being dead.
- Jossed when he did appear as a character in Risk of Rain, and it is implied to be the same individual.
