First up, you have to be a fan of point and click adventure titles to bother with this one. It's not very accommodating for those who aren't used to the genre.
The setting of this game is just incredible, you really do get drawn into the city and feel like the outsider. The level design is brilliant, yet simple; you start on the top level of the city (the lowest class is the highest up and the social elite reside at ground level) and gradually work your way down. You can always backtrack to earlier levels too, which unexpectedly becomes a requirement of several puzzles.
Voice acting is great, if inconsistent (bizarre mixture of American and British accents, and the opening cartoon seems to feature Australians). Gameplay wise there's not a lot going on, but you're playing this more for the experience. Also featuring the best robot sidekick ever. Reccommended.