In real life or with regards to this game? IRL it's "A brain-machine interface that is implanted into the top of the skull with electrodes"
With regards to SITTSM, it's an amazing new demo which will eventually be part of a very fun complete game.
Viewing post in Stick It To The Stickman comments
That would be the Neurolink Demo - You can click "Download Now" above these comments and choose to download the demo or you could try using the itch app if you're unfamiliar with installing things. https://itch.io/app