import samples with slice markers?

Is it possible to open two instances of Renoise at the same time? Two songs open at the same time? if so how do I do this on a mac?

I’m not sure if this has changed in newer versions of OS X, but as far as I know you need to make a physical copy of the Renoise application itself. Just copy/paste/rename it within your Applications folder. Quite silly, but it does work.