The map is primarily an expanded version of the original mansion from Jet Set Willy, with only a few new elements over its predecessor several of which are based on rumoured events in JSW that were in fact never programmed (such as being able to launch the titular ship in the screen called "The Yacht" and explore an island).

Jet Set Willy II was originally created as the Amstrad conversion of Jet Set Willy by Derrick P. Rowson and Steve Wetherill, but Rowson's use of an algorithm to compress much of the screen data meant there was enough memory available to create new rooms.

Rowson ported the game to the Spectrum alone as Steve Wetherill had moved to Odin Computer Graphics.

[2] It has a number of small differences, including the loss of coloured backgrounds in certain screens as the CPC version ran in a 4-colour display mode.

[3] Its release as Jet Set Willy II was less well received with Sinclair User's Clare Edgeley calling it the "biggest rip off of them all",[13] while Home Computing Weekly accused Software Projects of "trying to flog it as a new game".

While reviewers called the game dated, particularly criticizing the graphics as laughable and "stick-like", they conceded that the gameplay was still "pretty excellent" - the same reviewer who accused the graphics of being "stick-like" also stated that it was "one of [his] all-time favourite games" and "worth a peek".