Can I complete Rosetta Stone lessons just by completing unit's milestones?

Just forget RS completely!

RS is ridiculously overpriced, overrated and overhyped. All it does is make you repeat simple things like a parrot, nothing else. No context-based learning, no feedback, no grammar teaching, no conversation, no nothing. Cash-in for absolutely nothing, because this will never ever be able to replace real face-to-face language lessons nor other "conventional" language learning methods, nor make anyone fluent in any language, let alone master one. Please stay well away from these kind of "gimmicks"!

It's not a uniform program, use it in a way that benefits your learning, try the milestones then if you feel you need improvement in other areas you can always go back.

Viel Glück, Freund