I've been meaning to make something like this since 2008 when I found out that the icing on the cake didn't have to be a disadvantage. Other stuff kept getting in the way when I wasn't being forgetful or lazy. Since I'm going to be moving soon, it's hard to concentrate on anything major, so I took a couple of days and made this little program while I had the chance:
ex_shoot_with_scrolling_2018y_09m_28d_1825t.bin 4KB 78 downloads
It's unfinished and I'm not sure about the sound effects, but it's good enough to show to people. And at the moment, you can move your ship in all directions, but it doesn't seem to be necessary. I'll probably remove the ability to move left and right in the next version.
Press the fire button to shoot or flip the left difficulty to A to shoot without needing to press the fire button. The enemies will get harder to destroy the longer you play. They are worth 20 points. A bonus item will appear once in a while. It is worth 100 points.
The bar to the right of the score will decrease if the enemies get past your ship or if your ship hits them. Game is over when the bar is gone.
High score is remembered until the Atari is turned off or the emulator is closed.