scorptatious said:
Oi, if you want to talk about my posts, then just come out and ask me ;-P
But to answer your question, there are several things that can be named objectively bad in a game. Bugs, glitches, poor controls, poor level design[footnote]Indicated by the player losing their way easily or not knowing what their next goal is[/footnote], graphics, aesthetics[footnote]Indicated by either a lack of or simply bad aesthetic planning and consistency[/footnote], bad voice acting, and bad narrative or bad narrative pacing. And as was an issue with Aliens: Colonial Marines, a misleading demo or trailer.
On the other hand there are lots of things that are subjective, as well. Aesthetic style, type of story told, archetypes used, gameplay structure, game "type"[footnote]FPS, TPS, platformer, tower defense, RPG, RTS, etc.[/footnote], mood, themes, how much of a reward and/or satisfaction the player gets from the game, and how that reward and/or satisfaction is earned. As an example for the last one, a lot of the pleasure the player derives from a Pokemon game is tediously building your team and building them up one level at a time. In Half-Life, there is no leveling, and that progressive satisfaction comes from completing setpieces and learning more about the story.