...was especially effective because the scenes (presumably) take place at night. Or was the movie black and white? I've always thought a strength of the original Godzilla movie was the fact that it was in black and white. Godzilla is so much more impressive that way.
Most of the scenes did take place at night. As you say, that did help to make them more effective. When watching the newer movies, you sometimes do get the feeling that these giant monster scenes are being filmed in an enclosed area, though, especially in Godzilla Vs. Space Godzilla. You don't really get those wide open outdoor scenes like in King Kong Vs. Godilla and Godzilla Vs. The Thing.