Pretty sure the Traveler changed the gravity on the planets it touched (Mars, Mercury, Io, etc.) to be the same as Earth for some reason. I guess it knew we were going to explore the Sol system?
Nessus’ gravity was probably changed by the Vex for their own troops.
Titan and Europa most likely had artificial gravity for the colonies that lived there.
I’m not sure about Earth’s Moon. It’s possible that the Traveler’s touch extended to it from Earth or that the Hive did something to it.
Terraforming. The Traveler did all that for us. Oh wait, I mean "video game logic..."
Sorry, I saw all the other comments and felt left out for not giving a sarcastic answer. God what is wrong with me today?
Probably Engine Limitations
And there should have been sound differences in space, not a big deal bit with no air in space sound travels differently
And also firearms don't work in space, we went over this in COD:Ghosts
I know its nit picking, but it could have been a little more immersive
Still a cool level though, also low gravity PvP when ?