Downloaded the newest version and tried it in WinUAE and Denise emulators. Looks like "down", to activate the shield, no longer works, even if you start the game correctly (by pressing "up") and without using Fire-2 button once, because then it's deactivated and would be correct, but no matter how I start the game, Firebutton-2 always works for the shield and the direction "down" never. Have not tested it on any of my real Amiga500, but WinUAE and Denise have a very high compatibility rate, I would be surprised if both emulators behaved differently than the original computer here in this point (but, possible is anything).
Nice. Activating the shield with "down" works now. Was Fire2 for the shield now completely removed?
By the way, when i played the game longer, i had it a few times, that the parts of enemy sprites, that had already been shot, were not always completely removed from the screen immediately. It takes a while and then, in isolated cases, you can still briefly see a part of an enemy, that has already been killed. Happens not often, but happened a few times here so far. Apart from that, this beta-version plays well, already now. Looking forward to the final release.