Simplistically it really is a "small chunk" offense vs "large chunk" offense. West coast emphasizes short, high-percentages passes and particularly involves the RB in the scheme with short passes that act as runs. Slants, quick slants and quick outs are favorite plays in this scheme as well as the occasional sprint out made famous by "The Catch". A vertical offense, usually credited to "Air" Coryell(sp?) concentrates on deep, longer-developing pass patterns with more go routes, post patterns, fades, etc. It is not as high-percentage but big plays are truly that. Also deep passing opens up the running game more by forcing back DBs and even linebackers.