These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: The Breach
Anticlimax Boss: All of them. As long as you don't get pummeled too badly by some of their attacks, every boss dies after a few seconds of constant fire. Then you start the next mission on full health. It's often safe to simply stand in the same spot and shoot, taking blows as they come.
Ass Pull: The ending. Apparently merely having an airtight suit, heroic willpower, an automatic shotgun and a proven ability to completely resist The Corruption can stop you from falling prey to The Corruption.
You could make the argument that the new ending is as much an AssPull as the old, as there's literally no explanation how a guy in a supposedly air-tight suit falls prey to The Corruption. Even if you manage a no damage run, he mysteriously winds up with a parasite inside of him anyway. It literally makes no sense.
Maybe it took a long time to develop? The ship logs mention having no clocks, the whole ordeal could have taken months or years before they grew antennae.
During one of the visions you can either shoot the ship's former medical officer or do nothing and let the flying creatures touch you. It leads to a Game Over, but there is also an achievement for allowing it to happen.
Demonic Spiders: The butterflies, yellow cultists and... whatever the hell the white things are.
Fridge Brilliance: The cultists were mutilating and sacrificing each other, either uncontrollably as part of the transformation cycle or willingly for some sort of religious reason.
More Fridge: The mutants could have been killing weaker minded cultists specifically for a nightmarish gore-display.
Or because that would actually help open the portal. As one of the last logs by the now insanechief medical officer says, "The gods will use our abject flesh as a portal, and what was worthless will become holy. Pain is nothing compared to the reward"
Game Breaker: The Spread Shot upgradelets you do triple damage to any enemy that gets too close, ripping it apart in seconds, or shoot enemies from an angle so they can't bear down on you. And it's available very early on.
Nightmare Retardant: This is a horror-themed game, but mowing down five enemies at once significantly lessens the scare factor.
Squick: One of the ending cutscenes shows a woman birthing a giant insect.