In the computer room at Fjerritslev Gymnasium, we used to play this QBasic demo game a lot. So much so, that 'playing Gorilla' became a euphemism for something entirely different. It is a basic artillery game, similar to Scorched Earth, which we ended up playing a lot as well.
Screenshots marked with 🍒 are created by syltefar and are considered public domain, free to use for anything. If you want to, you can note where you found it and link to this page.