To add something, I will give a game a lot more leeway if it introduces new features over a game that aims to be everything for everyone.
For example, Psychonauts has its issues compared to a game like Ratchet & Clank. But since Tim Schafer tried to create something special and really succeeded in some regards, I'm willing to forgive some of the gameplay and technical issues with the title. Ratchet & Clank, a decent but middling platform in its own right, has a few less issues but since there is nothing truly extraordinary there, gets knocked down harder for its own faults.
Or Mass Effect vs. Oblivion... Bethesda tried to be everything to everyone and ended up with a completely mediocre game overall. It had some good ideas and implemented a few of them well, but when compared to Mass Effect and its amazing dialogue system and its cinematic take on gaming, Oblivion will get knocked down a notch for its mistakes (of which there are many) while Mass Effect gets a bit of a pass for its textures and completely bland non-story world environments.
Or check out my new webcomic: http://selfcentent.com/
