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.
HSQ: Extremely high, the whole game is basically one cool thing stacked onto another cool thing from start to finish.
Narm: The punching sound effect sounds more like slapping. The animations where an alien beats Lester into submission, or when Buddy gets into a fistfight with another alien don't help, either, making it look like everyone is just getting into intense slapfights.
Porting Disaster: Comparing the Sega Genesis and Super Nintendo versions of the games, both feature a new sound track. While the SNES version has better audio quality, it lacks in performance (the game will slow down a lot of times), and, believe it or not, load times!
Some may consider the 3DO version to be this. Despite some nice visuals and a good sound track, and teasing the fans with a sequel, the common complaints included the updated backgrounds and soundtrack not fitting with the atmosphere and what is going on in the game. Also, the sequel was never released on the 3DO.
Sequelitis: The first game was great, but hard and yet forgivable. Heart of the Alien is a lot harder for the wrong reasons, and looks comparatively worse than the first game. The big thing that saves it is that it includes the best console version of Another World at the time, complete with the best soundtrack for it.
They Changed It, Now It Sucks: Some people complain that by making the background more detailed in Anniversary Collector's edition it ruins the minimalistic art style that makes the game so atmospheric. But that is nothing compared to the 3DO version which has a very generic sci-fi art. Though the 20th anniversary edition averts this by providing the option to play the game in the original graphic settings.