I have some questions about La noire?

alright so here's the deal... i preordered l noire and payed 60 bucks for it with a little dlc that came with it.... now today after playing for max 5hrs, i found out that im already halfway done with the game.... (White shoelace slaying in homicide).. i realize that there are a few outside missions as well.... 40 i heard of just chasing down cars, etc..... is there anything else to do, and if so what? online mode? it seems like a waste of 60 bucks to me... yea i know the game looks pretty cool and is pretty fun, but i feel its too short... anyone else? also, for ps3, whats the deal with it not being in 1080p... look on back of cover, all other games i have have 1080p, but this one only goes up to 720p