When I analyze a game, I like to look at what impact each individual element has on the greater whole. A game can have an outstanding soundtrack or an abysmal storyline, but they alone do not constitute the entire game. Graphics, music, controls, gameplay, etc. all work together as a team to create a complete package; no aspect of a game exists in a vacuum. Examining how each aspect of a game contributes to or detracts from the overall game experience has been invaluable in distinguishing between which games are legitimately good or bad, and which games I simply do or don't like.
Shining Force: Resurrection of the Dark Dragon is perhaps the best example I have of a good game that I simply don't enjoy. As a tactical strategy RPG, it's very solid: it has well-designed challenges, a fair amount of customizability, interesting locations, plenty of secrets to find, a variety of unit types for you and your enemies, and a decent plot that drives the story. I have no qualms with the controls or the music or the graphics. It's a good game. I couldn't stand playing it. I'm a completionist and a perfectionist: between losing half my army in every battle to sloppy tactics and passing up half of the one-chance-only items in the game because I'd burned most of my money on reviving my team, I had a hard time liking the game. I felt the rift between how I was playing and how I wanted to play continuing to grow, with no way to close it but to restart and try again from scratch—and if it was heartbreaking to replay a single battle after pouring everything into it and losing, imagine how I felt about the prospect of replaying every battle, with no guarantee that the results would be any better.
On the flip side, there's Light People on Fire. I reviewed this game for a "Flash Flood" column on GameCola about games for terrible people. The graphics consist primarily of stick figures and fireball special effects right out of Microsoft Paint. The gameplay consists of lighting people on fire. It takes about two or three attempts to master, and about two or three minutes for the game to become utterly repetitious and pointless. But the concept of a stick-figure tree creeping around town and bursting into flames at will, combined with the abrupt musical transition from tranquility to heavy metal when the blaze begins, is hilarious to me, if only for a few minutes. Light People on Fire is not a very good game, yet I enjoyed it enough to rate it a 3/5, which is better than what I've given to half the Zelda games I've played. That doesn't mean the game is better than Ocarina of Time; it just means I like it more.
I know; I'm an idiot because OoT is amazing and my face is stupid.
But I understand myself well enough to know that Zelda really isn't my style, so saying I like some slapdash Flash game better than THE GREATEST GAME OF ALL TIME isn't really a criticism; it's a statement of preference. A statement of poor taste, perhaps, but an honest one. If anything, I'm mellower and more objective about games and series that aren't my style; there's less for this perfectionist to nitpick when it's clear that addressing the "flaws" would change the game into something it never had the potential nor intention to be.
Understanding the intent of the developers and the time and place where the game was made are also important. Kirby's Adventure lets you easily and regularly absorb the abilities of the enemies you meet; is it the developers' fault that the game is so difficult and boring if you aren't taking advantage of those powers? Frogger for the Atari 2600 doesn't look like the latest Call of Duty; does that mean it has bad graphics? A little perspective goes a long way in rendering a fair judgment of a game.
Ultimately, perspective is what it's all about for me: understanding myself as a gamer, trying to understand the mindset of the developers, and looking at the game as a whole package. Is the game fun? Why, that's just scratching the surface.