As a whole, strange or not, it is easier to understand written Russian, the more high-brow and literary, the better. The more colloquial, the less the comprehension. This would probably baffle you, but there is a simple reason for this: Modern Russian is actually a hybrid of two languages, Old East Slavic and Old Bulgarian. And I say Old Bulgarian and not Old Church Slavonic because the various “redactions” of OId Church Slavonic (Bulgarian, Moravian, Croatian, etc.) are very easy to distinguish, and Russian is based on Old Bulgarian. If I can make a somewhat dumb comparison, Old Bulgarian is for modern Russian is what Norman French is for modern English: an endless source of loanwords.

I also need to say that the reverse also applies to Bulgarian, i.e. there was heavy borrowing from Russian in the late 19th century, on that exact same assumption that Russian is based on Old Bulgarian, but it was very indiscriminate, and resulted in the borrowing of many Russified old Bulgarian words as well as some Russian-Russian words. But anyway, this reverse process was not so extensive. So this is pretty much the conclusion: understanding grows from younger to older generations, from colloquial to literary speech and from spoken to written Russian.