If I were to buy this game , can I download it to different laptops with only one purchase or I need to purchase the game everytime I download the game?
As long as you have an account, which you have, you won't have to constantly buy it. Just click on your account and find were your purchased games are stored, then continue from there.
If you return to this page, it'll still ask you to pay up, so do it from your profile if you own the game.
