Yes! Civ3 plays entirely differently from Civ4.
Civ3 rewards fast expansion and LOTS of cities/towns, whereas Civ4 rewards building up individual cities and you'd go bankrupt if you built too many too fast.
Somewhere here is a thread on what Civ4 players should NOT do in Civ3. It was written a bit "tongue in cheek", but most of the info is absolutely correct. I'll see if I can find a link for you.