The only feeling I can aliken it to, is the first time I played GTA III. Back to Skool blew my five-year-old mind. I had not long before started Primary School, and unbelievably through my ZX Spectrum, I could enter a portal into an alternate world where I was literally the worst pupil ever and wreak absolute havoc.
Back to Skool did have structure/ a path for its hero Eric, but to this day, I still don't know what it was. Like contemporary sandbox games, I purely reveled in breaking rules and evading capture (though the Headmaster always got me in the end).
The freedom to brazenly up and walk out of classes, randomly punch other students, write swear words on the blackboard, chuck stink bombs, fire catapults and shoot water pistols at unsuspecting innocents made Back to Skool a perpetual spring of mischievous joy.
And all of this on a 128k ZX Spectrum?
It even had a great theme tune, which I can still hum today...