Released on; Commodore VIC-20 in 1981.
Text taken/edited from this blog page on the Llamasoft web site:
Next up is possibly the longest lived game I’ve ever done:
“Deflex V” (again with the arbitrary numbering system). The first version of Deflex was made on the Commodore PET while I was still at sixth form college in 1979, and the latest version was released on iOS, so it’s a game with a long history. It’s about as sparse looking a game as it’s possible to make on the Vic, with the graphics consisting of nothing more than a blob, a number, and the “bats” made out of diagonal lines. Nonetheless it’s still actually kind of fun to play. We did do a much fancier version on the Speccy and a not particularly great looking version on the Atari 800.