Ultra Space Invaders

Game input holds PET matrix keys down until you physically release them, which is best for arcade games. Type input keeps the original short-tap queue for entering BASIC commands.

Charset Auto lets PET software switch normally. Graphics or Business forces the selected character ROM for compatibility/testing.

Changing RAM or ROM resets the PET. Some programs need ROM2/ROM4 or 16K/32K.

The sound slider controls the emulated PET VIA speaker. Modern browsers require a click before audio can start, so Start Game also enables audio.

The emulator has an IEEE-488 device at address 8 for loading/saving .prg files. D64 disk images can also be inspected for PRG files.