5.5? It deserves a better rating. It's a great game if you play it, read my review.
Assassin's Creed: Bloodlines' graphics are very good for a PSP game; Do not be fooled by the quality of videos on GameSpot, the game looks really good when you play it yourself. Honestly, I never knew PSP could handle such a game without lagging and all that but it works perfectly.
I must say this game is very easy as most of the times, the guards don't see us assassination people right in front of them, but it at least, saves time. The bosses are quite easy too and it's fun jumping from places and rooftops. No matter what GameSpot says, it's a very good game.
Just because the Xbox 360 had such a great game does not mean every AC game should be just like that, if PSP could handle that, who would want a Xbox 360 then? AC: Bloodlines is good in its own way and it deserves a rating above 8.0.