Thanks for pointing that out. The reason I used the old syntax was partly because I was learning with an old tutorial I found on the web (
https://sites.google.com/a/ruby4kids.com/gosu/home). I will change it to the current syntax.
Regarding the cannon blast frequency, because it is controlled by the code logic which specifies that cannon can only be re-launched either when it is outside the screen or when it is neutralised after hitting the enemy tank or a brick. Thus, it cannot fire multiple shots to be too powerful. In this case, the short distance attack is more advantageous.
I hope you have enjoyed playing the game :)).
I have had a discord account for a while. Now it is a good time to be more active!