Completed the game last night. Very good game, but would've been better without the RPG elements. Interestingly, the attempt at challenging fights, such as the Valkyries, are among the worst parts of the game, primarily because reading enemy movements is handled poorly. The camera being close to Kratos makes for some very intense combat and looks really good and detailed, but it also makes it really hard to see what the harder enemies are actually doing, especially if they're in the air. Additionally, the harder optional encounters rely more on being a sufficiently high level than being good at the game mechanics. The lock on camera is particularly bad when dealing with flying enemies or enemies that move around a lot.
The boss designs (mechanically, not visually) are among some of the most boring moments in the game... All you're doing is hacking away at a damage sponge, occasionally avoiding one of the two or three different attacks the bosses have. They're tedious...