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.
Gameplay Derailment: A lot of people complained that the vehicles derailed the fast gameplay of UT3, even when vehicles aren't available in common gametypes. (Deathmatch, Team Deathmatch, Capture The Flag... well, there's just one exception, but still...)
One of the Bonus Pack 2 maps from Unreal Tournament 2004, AS-BP2-Jumpship, retells a story about a squad of Izanagi soldiers infiltrating Liandri space and hijack a jumpship in order to be able to make space jumps without the need of a gate. Fast forward to this game, and another Izanagi team, the Ronin, hijacks a ship in order to jump to Necris space.
Akasha's first line in the final match. Until the free reboot, the series wouldn't see another installment for a long time.
"My patience for games has worn thin"
Misblamed: Although often referred to as a flop, and even one of the biggest failures in videogame history, in reality only the PC version sold particularly poorly on its initial release. The console versions actually sold pretty well, and even the PC version began selling a lot better (albeit at a significantly discounted price) when it was brought to Steam. Unfortunately though, even the console versions got overshadowed by the likes of Halo 3, which led to impressions that the series was yesterday's news.
Player Punch: In the final battle, you'll receive three "X has fallen" messages. Replace X for Othello, Jester and Bishop. And then, in the final cutscene, a Necris soldier drops a mortally wounded Jester in the floor. Cue Reaper swearing revenge against Malcolm.
That One Level: In the campaign, Torlan Delta, with the Leviathan and the two Darkwalkers, against the Krall.
Also, the final battle against Akasha in the higher levels.
They Changed It, Now It Sucks: The general reaction towards this game, going farther as splitting the mod community, with model/skin makers annoyed at Epic's screwing around with custom skeletons. Someone parodied it with a complaint generator.