Namaste dear sir, yes I see from the start that it is a game, so I understand that completely. That's fine. I enjoy gaming, on Hive especially.
As vegetarians we are brothers in spirit. Killing is not justified and no one likes war. However, in my studies of Veda, I have heard that the kshatriyas like Arjuna were allowed to practice archery by shooting animals. I could be wrong though. I am not in a position to find fault with the Vedic culture as I don't know the details. If Krishna spoke it via Vyasadeva, then I accept it.
In Ashwamedha yajna, indeed animals like horses were offered into the fire of sacrifice. However, in previous yuga the priest was able to revive the animal and so it was never meant to be killed. The priests were more powerful and could bring the animal out of the fire in a better body. There was no killing of animals in the original Ashwamedha sacrifice. Forgive me if I came across negatively, I am a humble student of Veda with very little insight.
I respect you highly for your vegetarian lifestyle bhai.
Wishing you all the best.