BTW, Bulgarian is harder to read for me than Serbian or Macedonian.
Although I do understand southern Slavic languages and I also managed to pick some words from Czech in the course of my life.
I have noticed that we have for a lot of things - two words, one slavanian - that russian/serbian/polish/etc would understand, and one turkish-like that arab would understand.
My native tongue is Romanian and I grew up on the border with Serbia - I used to speak Serbian near-fluently (but lost it after 2+ decades of not using it); I also know a little bit of Russian. This language seemed similar to Serbian to me.
(Though, that might be because it has quite different spelling from polish. Spoken, it could be similar. It feels very ancient. :-))
Yet, I found that just looking at the samples I'm not having much trouble understanding it.
Suggestion: try to read it out loud -- it helped me quite a lot with Polish. And here too.