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.
Broken Base: The We Don't Go To Ravenholm... level. It's either considered the Best Level Ever or the scrappy for players, because it goes away from the traditional first person shooting throughout this level; having to rely mostly on the world traps and idle objects thrown by the gravity gun due to lack of gun ammunition. There's other debates regarding the level being if it's out of place for getting in the way of the war against the Combine or not and if the mission is too scary for some players having to fight through a town infested by zombies at night.
Triage At Dawn, an unexpectedly beautiful yet solemn piece that makes your escape from Ravenholm feel all the more rewarding. There's also the extended remix by DJ Dain titled That Long Train Ride, sometimes known as "Path of the Borealis".
Porting Disaster: It's no one's fault, really (the Xbox, while being the most powerful console of its generation, was not fit to run something as meaty as the Source engine), but the quality of the Xbox version is simply too far away from the PC original to make it worth playing.
The Playstation 3 version of The Orange Box was pretty shabby too, with Valve (at the time) not having that much faith in the PS3 and it being outsourced to another company entirely.