KQ5 for NES is a PAIN in the butt, since it requires the use of arrows to simulate the mvement of a mouse. I beat it once, when my version of KQ5 was currupted at the very end, and I couldn't see the ending movie.
Although, KQ1 was ALSO released for Sega (and I just remembered that now). I have yet to see how that plays (as I dont have a sega), but I may be able to make a run of that. Assuming I get the emulator and the rom and figure out the whole recording stuff, making a run of that won't be very difficult.
I've beaten every KQ game, have walkthroughs for all of them, have played them all to death (and in one game, I've even found a shorter complete path than the official walkthrough).
But there are other factors too. With the exception of KQ5 which is VERY linear and almost nothing can be skipped, there's a short path through all teh game (where you focus on how fast, and not full points), OR go for full points within the fastest time