Changing the size of memory or changing the ROM version forces a reset of the PET.
The emulator has an IEEE-488 device at address 8. It can be used load and save (.prg) files.
Some programs don't run on ROM1 and some require more memory than the default 8K.
SHOOT is a simple timing and reflex game. A PETSCII cross drops from the top of the screen, and you have to press a key at just the right moment to time your shot. I thought at first that you had to try and lead the target, but actually, you're just trying to stop the falling target at the moment it passes the height of the barrel of your gun. Hitting the target results in the tamest explosion ever.
You set the speed of the falling target by choosing 1 of 5 levels. Timing at the fastest speed is tricky; I only managed to score 2/10 even after a bit of practice.