Started playing at work on hard difficulty. This games looks absolutely amazing. This is by far the best looking PSP game.
Completed 7/39 chapters.
Completed 19/39 chapters. Played for several hours on the plane from Heathrow to San Fransisco. Playing on Spartan (Hard) difficulty, the game is tough, but fair. The characters and the grand vistas are beatifully rendered, albeit with a pretty low frame rate.
Completed 27/39 chapters. Ghost of Sparta saved me from boredom today, when I was flying back from San Fransisco via Heathrow to Copenhagen, and at Copenhagen airport, where I spent 5 hours waiting for my lost luggage to arrive with another plane from Heathrow.
Completed 28/39 chapters. Back home, safe and sound. I needed a video walkthrough to not double-jump the gap in the Canyons of Sorrow, because it was a quick timey jump. Bad design choice, I think. The character of King Midas and his fate is pretty cool, though. If only the PSP could render some more convincing gold.
I found my good old PSP in a box, charged it, and fired up Ghost of Sparta. When you come back to this game from a break, it's not a pleasant experience because of the awful frame rate, but you do eventually get used to it. The game is still fun and challenging, and I managed to complete 30/39 chapters.