As a reference, Command and Conquer: Generals contained building capture by infantry. The mechanism was that infantry would kneel and plant flags next to a building which would start flashing at an increasing rate (to show progress) until it was captured. I think that the capture timer reset even if you stopped the capturing process for 1 second. Once the buildings was captured you could train units of that nation. This made capturing the command centre very valuable since you got access to all of the buildings of that nation, so could play as both civs. Should we do this for 0 A.D.? It was common to capture buildings and instantly sell them to gain money and prevent them being recaptured. I think it would be worth removing the delete feature for buildings (maybe have a deconstruct action which requires builders) unless we want the capture feature to turn into a raze feature (capture and delete). Regarding gates, what do people think about making gates (and maybe walls) orientatable? So they would be capturable from one side (and wall towers would be garrisonable from one side only).This would be more realistic and add some interesting gameplay but would make the gui more complicated when choosing the gate upgrade.