I asked the programmer Chris Sorrell, here's his reply:
We’re talking about JP1, right? For that one I vaguely remember that the loading/intro sequence had some kind of extra animation if you had a 1Mb system - but this was a built in switch that was part of the shipped version.
As for JP2, that also had a built-in extra for 1Mb systems: it loaded all maps into the extra memory and never had to load from disk.
…But that’s all I know about - oh, unless we’re talking about an *AGA* version of the JP2… I recall a colleague of mine at Millennium spent a while working on enhancements for an 'Amiga CD' version of Robocod. It wouldn't surprise me if those improvements were rolled back into an AGA targeted version disc version (AGA systems had 1Mb as standard I believe?). I'd be surprised if there was ever a special version of JP1 though - all the AGA work came after JP2 had shipped. …Since all my James Pond work was done outside of Millennium I can’t totally vouch for what extra versions they may have done without my knowledge but I’m pretty sure AGA systems would be the angle here.
Hope this helps!