Many times when I'm working on Flash games I'll find that a particular combination of keys held at the same time doesn't register, e.g. LEFT, DOWN and SPACEBAR.
I know from my days playing Doom this can be caused by the keyboard hardware, but surely technology has moved on since those spongy beige PS2 keyboards?
So my question: are these problems caused by Flash, by the hardware, by the operating system, or something else?
it's still keyboard hardware limitations. http://en.wikipedia.org/wiki/Rollover_%28key%29
The problem also occurs in Java games so I suspect it's on the OS level or lower.
What you want to do is to have Boolean variables and turn them on and off while they are pressed and un-pressed. Flash has a combination of just a couple of keys(i do not know why) but you can easily get around it by just keeping your variables up to date when they are pressed and released.
