I just finished Katamari Damacy. I started playing Monday night, now it's Wednesday night. I guess I played about 8-12 hours in total. Here's what I liked about the game:

• The save game selection screen
• Looking up in the tutorial level
• Looking down in the constellation screen
• The TV in the living room
• The King of All Cosmos and his parenting skills (and his diary)
• The Prince
• What you see when a level is loaded
• Starting with a 1m katamari and going all the way to 300m in one level
• Wiggling creatures and screaming people attached to my katamari
• Despite the fact that aforementioned creatures and people get collapsed into flaming balls of gas, it's a non-violent game
• What happens when you lose a level (somehow I saw this a lot on star 7)
• The music
• The fact that it's a short game, but there seems to be genuinely cool hidden stuff
• The very satisfying ending (I didn't even get the 'UN mode' even though I'd seen it at GDC...)
• Easy access to everything you've seen or unlocked
• The visual style and general upbeat wackiness
• "Oh! I feel it! I feel the cosmos!"

Update: Fixed stupid typos.