Thanks for the feedback, about the screen centering, there's a really good post by Earok here: https://eab.abime.net/showpost.php?p=1540201&postcount=2038
In a nutshell: "screen center is ambiguous on Amiga since the overscan area on left/right and top/bottom isn't even", so in other words, there isn't too much that can be done about it. About the other issues, they are all well known, specially issues after game over like cumulative weapons (your flamethrower will also fires a bazooka projectile at same time, which actually benefits the player so I left these in the end of issue's list, focusing more in the stuff that actually breaks the game).
Thanks again for the detailed posts and thanks for playing!