Great game
Good game
Bad game.

5 stars with half-stars is probably the most meaningful scale to me. A 88, 91, and 93 could probably all be roughly equal to me, depending on the games, so such a fine-grained scale doesn't really provide much extra value over a coarser scale. On the other hand, a scale from 0 to 10 is heavily biased towards the upper end, which I don't feel like is the case with a 5-star scale, with or without half-stars: 3 stars is roughly in the middle, just as 50 points is, but whereas I would call a 3-star game pretty average, I'd certainly call a 50-point game thrash. The equal of a 3-star game is actually something like a 70-point game, or maybe even more, because I would expect most 3-star games to be pretty passable, but most 70-point games are probably getting into the risky territory already. Also, I feel like using stars instead of precise points puts more focus on the review itself, which better acknowledges the complexities of rating a game.

Of course I don't really rate games a lot, so who cares, but if I did, I'd probably use a 5-star scale with half-stars.

In ascending order:

Not Fun
Fun
Nintendo

I'm a simple man. =P

I usually define them as: One of my favourite games of all time, I really love this one, I like this game, or this game is not for me. There's no real score, no real reason, it's just how I feel about them. For me, the positives outweigh the negatives, and the negatives only really mean anything serious if I don't care much about the positives.

Some of my most disliked mechanics exist in or originated in my favourite games. For example, Xenogears is my favourite game of all time, it is also the birth of one of my least favourite mechanics of all time - battle combos, that is combining multiple attacks when a single attack would suffice.
Final Fantasy 6 is another one of my favourite games of all time, it was also the birth of mini-game battle inputs, another thing I loath in RPGs.
One of my least favourite things in any type of game is dungeon crawling, yet I love NES's Metroid, and that game is one big dungeon crawl.
Shallow Mary Sue characters are also a giant turn-off for me, but Skies of Arcadia somehow won me over.

I think it's silly that people have one all-encompassing rating for a game that takes into consideration both its value as a work of art, and how well it is (or isn't) technically realized. So many games have come and gone where they have great stories/music/atmosphere/setting/etc and even great gameplay in theory, but are lambasted for having glitches or a poorly optimized port. I understand that those issues are relevant and stop the player from immersing themselves into what the game is supposed to be, but technical issues are a completely separate problem.

What I'm saying is: You so often see people rating a very interesting game a 0 or 1 out of 10 because it came out with many glitches that are likely to be patched in the future, and then rate the blandest and most boring stuff a 6 out of 10 because even if it's uninteresting, it's functional. The scale is not being used well. "Functional" should not guarantee you a decent score.

I always thought games should have two scores. One for what they are as a creative work, and one for the technical aspects of it. That way it's also easier to rate games across several platforms: each platform gets its own technical rating for the quality of the port, but there's only one creative rating throughout. And while the technical rating could change over time with patches, the creative rating really shouldn't - with an exception for games with big DLCs that change the experience fundamentally.

5 stars with half-stars is probably the most meaningful scale to me. A 88, 91, and 93 could probably all be roughly equal to me, depending on the games, so such a fine-grained scale doesn't really provide much extra value over a coarser scale. On the other hand, a scale from 0 to 10 is heavily biased towards the upper end, which I don't feel like is the case with a 5-star scale, with or without half-stars: 3 stars is roughly in the middle, just as 50 points is, but whereas I would call a 3-star game pretty average, I'd certainly call a 50-point game thrash. The equal of a 3-star game is actually something like a 70-point game, or maybe even more, because I would expect most 3-star games to be pretty passable, but most 70-point games are probably getting into the risky territory already. Also, I feel like using stars instead of precise points puts more focus on the review itself, which better acknowledges the complexities of rating a game.

Of course I don't really rate games a lot, so who cares, but if I did, I'd probably use a 5-star scale with half-stars.

I think it's silly that people have one all-encompassing rating for a game that takes into consideration both its value as a work of art, and how well it is (or isn't) technically realized. So many games have come and gone where they have great stories/music/atmosphere/setting/etc and even great gameplay in theory, but are lambasted for having glitches or a poorly optimized port. I understand that those issues are relevant and stop the player from immersing themselves into what the game is supposed to be, but technical issues are a completely separate problem.

What I'm saying is: You so often see people rating a very interesting game a 0 or 1 out of 10 because it came out with many glitches that are likely to be patched in the future, and then rate the blandest and most boring stuff a 6 out of 10 because even if it's uninteresting, it's functional. The scale is not being used well. "Functional" should not guarantee you a decent score.

I always thought games should have two scores. One for what they are as a creative work, and one for the technical aspects of it. That way it's also easier to rate games across several platforms: each platform gets its own technical rating for the quality of the port, but there's only one creative rating throughout. And while the technical rating could change over time with patches, the creative rating really shouldn't - with an exception for games with big DLCs that change the experience fundamentally.

100% or 100 point scale? A scale of 1 to 10? Five stars? Tier from F to S? What does your system mean for you? I'm particularly interested in how people use a 100 point scale to conclude at a score like 89 out of 100 instead of rounding to a 9.

I use a scale of 1 to 10.

1. Absolutely broken or unplayable
2. Extremly bad in most aspects 
3. Bad in most aspects
4. Poor
5. Average/Bland
6. Average/poor with fun and excels is some aspects
7. Good and plenty of fun
8. Great in most aspects with loads of fun
9. Phenomenal in most aspects with immense fun
10. Masterpiece and immensely addicting