You know what? This book is actually not that tough to read. Tough to process or characterize? Well, sure, probably. But reading and understanding it at the basic plot level is pretty straightforward actually. There are just a couple of things that might throw you, and guess what? Today is your lucky day because we are totes going to spill the beans on what to watch out for.
First, you've got your standard novel-written-in-a-different-time-and-place level of adjustment. You have to put yourself in the mindset of the 19th century, where extramarital sex was as big a no-no as violent crime. So, for example, it's a huge, huge deal that Nastasya used to be some dude's mistress, however involuntarily.
Second, you have to set your emotion reader on "Dostoevsky," which always means lots of scenes of people going kind of nuts, losing it, and screaming at each other. It's what's technically known as a "heightened reality" or "crazytown." Don't worry, it's not contagious.
And finally, there are the names. Oh, the names. Okay, a quick mini-lesson on the Russian language. In Russian, you can transform words by adding endings or beginnings (suffixes or prefixes) or by taking them away. For names, this means that any kind of endearments are created by taking the normal version of someone's name (say, Aglaya) and adding some cutesy-poo to it (Glasha). Even more confusing is that you can have several kinds of suffixes that all pretty much mean the same thing but make the name look way different (Aglayenka, Aglashka).
Also, the polite way to address a stranger in Russian isn't to use her last name (like in English when we say "Ms. Smith"), but instead to use her full first name and her patronymic. A patronymic is a fancy middle name that is derived from her father's first name and means daughter-of-so-and-so or son-of-so-and-so (so Nastasya is be called Nastasya Philipovna, because her dad's name was Philip).
And finally, Russian nouns have different endings depending on whether a word is masculine or feminine, so even though Ganya and Varya have the same dad, Ganya's full name is Gavril Ardalyonovich, but his sister's full name is Varvara Ardalyonovna. Whew. Many editions try to go easy on the name thing to spare readers, but not all—so just be prepared