price: from 15 EUR platforms: C64,C128
Provides two additional standard joystick ports via the user port.
Extend your C64's capabilities with the 4 Player Interface connected to the user port of your Commodore 64 or 128.
It provides two additional standard joystick ports. This enables up to four players with four real joysticks to play together on one computer.
The website also has a link to instructions / parts list in case you'd prefer to build one yourself. A number of games support this device and code examples are given if you'd like to add support to your own game.
Find out more / buy at: https://www.protovision.games/hardw/4_player.php?language=en