During this run I completed the entire Vice City Stories game achieving a 100% completion at the conclusion of the final mission. You will also notice in my game stats that I also have 100% empire attack and defending rate, proving that while extremely frustrating to accomplish, it can be done.
This was by far the most challenging thing to accomplish since the enemy gangs can counter attack while you are purchasing conquered property and take it over without you noticing. I found that by strategically taking over one gang unit I could position myself next to a save spot. This way I would take over a territory wait by the purchase sign for a couple seconds for any possible counter attack. If none was present I would quickly purchase the site and then check my stats to make sure nothing happened during the attempt. If I was successful an enemy gang would then try to counterattack. If this happened I would race over and defend my territory and then quickly save when they retreated. Next I would reload the game so that my enemy gang hate was erased and no counter attacks would occur until I provoked them. I also found out that during gang wars during the early morning hours resulted in fewer immediate counterattacks while I was purchasing conquered territory. I won’t lie, I didn’t think this was possible and most of the time it was trial and error. If they had an immediate counter attack while I purchased the property I would restart and try again. Another pointer is to pick a gang, in my case it was the bikers, and take over all of their territory first before going to another gang. I choose to start these empire missions after you destroy the Cholo gangs via the Roberto’s “Havana Good Time” mission so you only have two gangs to worry about. Also note that you cannot wipe out the bikers until after the blitzkrieg missions.
After I beat the final, Last Stand, mission, I also complete the extra “Sky Wolf” mission that appears at the airport.