Wikipedia
Invade-a-Load was a fast loader routine used in software for Commodore 64 computer. It was used in commercial computer games that were stored on Compact Cassette tape and loaded using the Datassette.
Invade-a-Load contained a notable feature other than its fast loading routines: While the actual game was loading—a process which usually took a long time, even with optimized loader routines—the loader allowed the user to play a smaller game to pass time. The game was a clone of the famous Space Invaders game. The minigame was loaded in under a minute, providing entertainment while waiting for the actual game to load which could take a further five to ten minutes.
It mostly appeared in games sold in the United Kingdom, as, by the time it was written, the Commodore market in the United States had mostly switched to floppy disk media.