Why does halo 3 have higher ratings than killzone 2?

[Scoobes]

-Brand-name: with 2 previous games that were hugely popular, any suprise at the sales? Killzone 1 wasn't exactly considered AAA.

-Mass Advertising: Halo 3 has to be the most over-hyped and over-advertised game in history. MS must have spent a ridiculous amount. I'm sure this would have had some influence of reviews as well.

-Immense multiplayer in Halo 3. I'm not a big fan of the Halo games in general, but the multiplayer features are huge. Killzone's got good online multiplayer, but hasn't been refined as much as Halo 3 and no offline/co-op support.

-Halo is more mass market friendly. In the UK Killzone2 is rated 18+, and the graphics are very real and even most of the adverts are 18+ (I think Halo 3 is a 12A, 15+ at the most). Most responsible parents aren't going to allow there kids/younger teens to play Killzone 2. The graphics and enemies in Halo aren't as realistic, and are much more open to mass market.

I actually think the single-player campaign in Halo games to generally be average (too repetitive... although the vehicle sections are fun, the rest of it I find rather boring), but a lot of people seem to enjoy it and the story.