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.
Alternate Character Interpretation: One fan theory states that Macready is actually a Thing that's flying to the mainland, and helped Blake defeat the Whitely Thing, so as to divert suspicion away from itself. It would explain why Macready survived for so long in the arctic climate, and Childs did not.
Game Breaker: In the third boss fight (which is a giant thing-tentacle hanging from the ceiling) there is seemingly no safe place for you to hide without getting hit by the boss creature, forcing you to keep moving around to dodge its attacks. There's actually a very easy way to prevent this however: stand literally right against it. Due to some fault in the programming it can reach anywhere in the room, except a foot or so in front of it.
The Problem with Licensed Games: Opinions differ on how much this applies to the 2002 game, though even its detractors generally tend to admit that there are many far worse licensed games out there (well, unless you're Spoony...)
That One Level: One stage late in the game has you going down a seemingly endless staircase. Sounds easy enough...except there are automatic turrets on every level (that can take up to five grenade hits to destroy), scalding steam vents, seemingly endless streams of scuttling creatures that pop out of dead bodies (and attack you from front and behind), and the medic, your only hope of surviving the stage, turns into a monster at random points. If you don't have enough health packs on you, or enough firepower, it's impossible to get through the stage.