Quality in video games is certainly more objective than in painting. There are a lot of aspects of a video game that are not fully subjective: does it have a control scheme that feels good and generally works, does it run well, does it have a reasonable difficulty level or on-ramp for learning to play it, etc.

In judging painting, you don't end up with a lot of complaints about things like "I like the way it looked but it kept falling off of my wall", whereas if you have an unstable game...