I can't remember if Lemmings did this on actual hardware or not but when you move the cursor around quickly, when playing it causes the game to slow down quite badly.
This then results in screen tearing and breaking up sound.
I get the impression that the screen isn't being drawn fast enough but I can't figure out why.
I'm on a Mac Pro with Leopard and I've tried all the latest Basilisk II builds.
I have also tried it with 7.5 and 8.1 using a Performa rom also different cpus 020 030 040.
Video performance is poor in BasiliskII (and in SheepShaver) compared with real hardware Macs. The same is true for sound. Especially applications with moving images, like many games, will suffer. In some cases performance may improve with lower (yes, lower) refresh rates set in the GUI or Prefs applications. Try 30Hz. and make sure JIT Compiler is enabled.
I am very interested in mac os 6-7 emulation on a PowerPC mac mini, but it seems to be in a VERY inaccurate stage. I have my hopes in Executor sources and mini Vmac... Basilisk and SheepShaver are SLOW and they both have very bad display, as you suggest.
Too bad CLASSIC in OSX 10.4.x is that bad for games...sloppy, VERY sloppy, slow as hell...even Lemmings runs SO BAD! But then again, I think it can't be helped.
Interestingly, Lemmings runs poorly in Basilisk II for Windows.
More advanced games run very well, but Lemmings always runs poorly, just as you described. Not sure why that happens.
Interestingly, the shareware demo of Lemmings is included with Executor (Windows, sorry), and it runs very, very well. I spent an hour last month playing through the levels. Such fun!
