I was really doubtful when Sony announced that the 'Petz' range was coming to the PSP, but this animal offering is just brilliant.
Firstly, the graphics are mind-blowingly realistic. Secondly, the whole game is designed around the concept of a TV show in which your hamsters are the stars. The different channels include news and sports as well as horror, romance and Sci-fi etc. These channels provide the setting for the Hamster cages and they look really good, lol!
Furthermore, your Hamsters' thoughts can be displayed on-screen (this can be turned off for those people who prefer their interaction with the hamsters to be more realistic), which usually provides truly witty - and sometimes crude - insights into the hamsters way of life!
Moreover, each hamster has a different personality, which affects the way in which they interact with you and the rest of their environment. Obviously this won't be a game that appeals to everyone, but if you only buy one game for your PSP this year, I recommend that you try this one... 10/10.