It is easy to make a "Direct Disk to Cartridge Port" by using the [[No$cart]] utility by [[Nocash]].
A number of unofficial cartridge games have been made this way and some have been even been sold in nice packaging and sold on Ebay . (Iznogoud, SaboteurSee [[Bootleg Cartridges]]).
It is nowadays a common feature to modify existing CPC games to take advantage of some plus features, mostly the [[Plus]]'s bigger palette, but often these remain on disk.