The problems you describe with KQ3 sound like a timer issue. Because
the game is running on a much, much faster processor than for which it
was designed, timed events can take much longer to occur than usual.
For example, there’s a section where you have to work out on various
machines in a gym. You’re only meant to do 10-20 repititions on each
machine. On a modern processor, it can require hundreds.
Use an application like Turbo, MoSlo or DOSBox to fix this.