One of the best PSP games to date. Accessible, fun, plays great.
Chains of Olympus is actually the first God of War game I've played, so the criticisms of recycled gameplay elements didn't factor into my impressions. But even if I had played through the other GoW games, the core mechanics are so fun and intuitive, I doubt they'd detract much from the experience.
This is pure action fun, accessible to a wide audience so you don't have to be a hardcore fighting genre nerd to appreciate the game in its entirety. It's an action game to be enjoyed, and I found myself laughing throughout the game at the over-the-top moves you can unleash. Boss battles are especially great examples of design, with a simple strategy to figure out and appropriately over-the-top button-response dramatic moves.
You'll probably finish the game in under 10 hours. Normally I'd cry foul but with I felt like I got my money's worth with GoW: CoO. There's not a dull moment throughout the game. The limited number of enemies and mini-bosses get recycled a bit, so toward the end of the game, it gets slightly methodical churning through all the trash mobs, so if the game were any longer, it would get really repetitive in my opinion. At the current length, it's just enough to feel fun without excessively extended.
Overall, this is my favorite PSP game to date and a remarkable achievement on a portable system.