Frustratingly bad.
For starters. The game seems just unfinished. The audio is quite flat for 5.1 surround. I honestly had to keep checking my sound system display to make sure it was outputting to all the channels. The graphics are, of course, over-the-top for vistas and cutscenes, but for the platforming and combat - there is something just off about everything. Kratos moves in such a wooden manner that [evade] is pointless. Likewise, [double jump] is completely broken. Don't expect much reliability, accuracy or timing with that one in a boss battle. Don't expect precision from either if you are being swarmed.
And that leads me to my main issue with the game: the difficulty settings are astronomically skewed. If you initially select Hard, be prepared to do a lot of the same crap repeatedly until you just happen to luck your way past a fight. Why? Because of the above issues meet an egregiously reprehensible respawn implementation in the game. Apparently, the developers are so in love with their sweeping set pieces that they want us to experience them over and over and over and over ad nauseam et infinitum. Their idea of scaled difficulty is to overwhelm Kratos in a small area with defective defenses against a multitude of leveled-up enemies who cannot be avoided vertically And laterally. Death is quick and often. Restart is also brilliantly without full health and often before a long intro (to an even minor battle) that is not skippable! And some of these "cutscenes" you have to actively trudge through for no reason just to get back to the point of inevitable reset.
I am all for a challenging experience but it has to be well-designed. And it cannot impede progress in the narrative. Easy Level typically means an all-offense approach will get you through. Normal Level requires some avoidance and some defensive tactics. Hard - more defense, combos, wise upgrades. Insane - hard plus precise timing, stealth, wait-and-see strategy. And all of those are fine if the gameplay mechanics of the release function and do so with balance to the enemy AI. Seriously, Santa Monica should have spent the wasted time of a multiplayer into polishing the interactive campaign portions which actually feel like a bad stiff multiplayer. One of the worst sins of game-making is undue repetitious gameplay in story mode; in multiplayer it is expected. But in this campaign, it causes a player to walk away from the console.
Plus, even if it were working, it is just the same old familiar GOW you've done five games before. And in this latest one, you'll be repeating enough as it is.