I took a shot at this on Super Metroid...bad idea. The game's quite complex and requires precise motion; trivial by now for me at normal speed, but at 200% it's much more difficult. Formerly trivial platforming became much harder, even if there weren't any monsters in the area. Plus, that little invincibility window after getting hit is barely enough to register that I'm not where I meant to be. I spent a lot of time standing on spikes. :( I did use savestates; Kraid and Phantoon both took multiple tries (Kraid particularly loved to toss me off of the high platforms repeatedly).
I am in fact still stuck at Ridley, with 9 E-tanks, 2 reserve tanks, and just not enough skill to beat him. Draygon oddly enough was cake, and Botwoon merely very hard to hit (went in with 105 missiles, came out with 6).
I did the early supermissiles, early Spazer, Kraid without hi-jump, and skipped Grapple Beam; that's about it for sequence breaks. Oddly enough, I got the mockball on my third try.
I don't know of any way to get less of a speedup than 200%; the only setting I have that appears to modify emulation speed is the turbo multiplier, which has only integer values. I'd like to try this at 150%; that seems like it'd be much more doable.
Also, I would make a .smv, except that every movie I've ever downloaded desyncs, so I suspect that any movie I'd upload would also desync. Is there a guide somewhere to playing .smv files on SNES9x 1.4.3 for the Mac? Or alternatively, I downloaded
1.5.1, but it appears to do nothing when I select the .smv file after choosing "Play Movie...".