Both Gears of War and Killzone are what I would call "very good". I wouldn't class it as excellent as that category is reserved for a select few PC games I play such as Crysis.
Killzones' graphics seem a little 'off' to me because they use a lot of visual tricks to achieve the effect and they don't hide them as well as games like Uncharted and Gears of War. This comes down to a difference in experience and what each developer was trying to achieve.
Tease.







