There are a lot of issues with the list.
My biggest issue is that some games are obviously placed on there to boost sales. Let's start with #1, Skyrim. Sure, it's a good game for many. But you have to assume it's sales have been slowing over time. You don't think ranking it the greatest PC game ever made isn't an effort to stem that tide a bit?
Anyone on the fence about many of these games might be swayed to pull the trigger on a purchase after reading the article.
You really think FTL is ranked the 18th greatest game ever on merit alone? Or do you think it just might be there to garner a few extra purchases? I'm not dogging on FTL, it's just an example.
In my opinion, as I've said, the suspicions that game reviewers inflate scores because they're 'paid off by publishers' are greatly exaggerated.
I think the rule is that they bend over backwards to not do that, while there are rare exceptions it happens.
I think the selection of Skyrim for #1 of all time is plausible and defensible, based on it being the 'last man standing' for large-budget RPG's and a deep, large, polished game.
And I don't think FTL begins to have the marketing clout to buy that influence even if it could be bought, really. It got an 89; it's likely just the author's opinion.
Some picks do raise questions, like especially that DayZ mod - it almost raises a question as if the person based on the early hype that had so much excitement.
As if they're unaware of the decelopments of a poorly rated release.
I won't put that in stone - I think Future Publishing, the company behind PC Gamer, seems to be struggling financially - look at the rest of PC gaming magazine, and they've had things like their very nice World of Warcraft premium magazine shut down - look at the comments in this thread, I may be the only subscriber here. But I very much doubt payola.
And that doesn't require an especially high view of the magazine's resistance to the money - it's just they have a system. Money seems to help in the *preview* section.
It's not uncommon to see games that buy advertising get glowing previews, followed by horrible reviews. I've commented on that before with blaring examples.
They know they can get away with the line of 'hey, it sounded good, but you never know until it comes out'. But that doesn't explain some of the extreme changes.
Now, if FTL had a review score of 70, it would raise more suspicions - but 89 and the broad love of the game makes that one plausible as well as the author's opinion.
Sometimes these things can be pretty corrupt and devious, but I'm giving more credit to PC Gamer despite the bad list. As an unverified conspiracy theory, airplane magazines have a list of 'best steakhouses in the US'. Rumor claims that ad is paid for by a front group for one of the restaurants in the list, to put themselves in good company.
Which in that case makes sense - why would some group have nothing better to do than sit around making a list and spending a fortune to advertise it, making them no money?