I'm not much of a gamer, I said FPSes because such games become really unplayable if a key combo you use happens to block, while you might be able to find a workaround in a RTS, for instance.
Mileages do vary, it seems.
I've played mostly FPS for the last decade on a Dell QuietKey (I doubt it's full NKRO), and never really had any problem with it besides the very occasional key not registering while I was crouching AND zooming AND moving forward AND straffing AND firing AND... well, you get the idea.
Also, from what I gathered around forums, it seems like quite a few people have problems with 2-KRO because they are using arrows keys or numpad for their movements.
If I'm not mistaken, the matrix at/around WASD is made in such a way that 95% of the time you won't be bothered (yep, that's a highly scientific statement).
Maybe that was your problem, Henry... or you may want to elaborate a bit more on "unplayable"... though it might not be the best place to do that :smile: