“Makey Makeys are fanastic - combine this with an OTG cable and a mobile phone (running an app created in defold) and you can create a real-life version of Keep Talking and Nobody Explodes - visit my website www.donot-open for more info.
Haven't tried the mouse functions on the back of the board, but everything else works perfectly, just as expected.
What I will say is this: this website also sells something called a Player X PCB for 7 quid which might work better for your project. Player X works as a gamepad with 12 buttons, rather than a MM which works as a keyboard, but for games made in Defold it's plug and play, as I expect it will be with many other applications that accept gamepads. So that's worth investigating. In terms of difficulty, both are exactly the same - plug the USB cable in one end, plug your buttons/keys/bananas/etc in the other end, and you're up and running.”