8-bit home computer games frequently had a mix of joystick and keyboard support, since (esp. on platforms like the zx spectrum where the users all had twenty bucks in the bank and couldn't afford luxuries like Anything Except The Computer Itself) nobody could assume a user actually had a joystick. but most of the home computers had no arrow keys, or if they did they had an asinine layout. this made controlling games miserable
if you were lucky, you got "wasd, but from the 80s" which means it was anything but WASD. one popular option was IJKL, which isn't too bad - it's still an inverted T, at least. some other approaches were the "diamond", e.g. IJKM. but what was most common in my experience, particularly on the spectrum, was a "split" layout, like QAOP, which kinda makes sense if you think about it. in all of these, there's just no telling where fire will be, it could be anything.
anyway i've been messing around with acorn archimedes games and i've found that the most common layout is ZX/', with fire on Return, and that's a new one on me. it's not surprising that no other platform used /', given that most didn't have those keys, but what i'm actually driving at is that the archimedes had inverted-T arrow keys, and a 10-key numpad, on every model. other platforms that had those things (PC, PC88, etc) used them by default, but I guess Archie users were just already acclimated to using letters.
