[1] He ported the SimCity computer game to several versions of Unix and developed a multi player version of SimCity for X11, did much of the core programming of The Sims, and developed robot control and personality simulation software for Will Wright's Stupid Fun Club.
He developed and refined pie menus for many platforms and applications including window managers, Emacs, SimCity and The Sims, and published a frequently cited paper about pie menus at CHI'88 with John Raymond Callahan, Ben Shneiderman and Mark Weiser.
Hopkins also wrote demonstrations and programming examples of the ScriptX multimedia scripting language created by the Apple/IBM research spinoff Kaleida Labs, developed various OpenLaszlo applications and components, and is a hacker artist known for his artistic cellular automata.
[5] The current version includes pie menus and is explained in depth in a video[6] released by Hopkins.
He added functionality to let kids create new disasters and agents (like the monster, tornado, helicopter and train), and program them like in many of the other games on the XO.