It works very well. But there are some tracks that are not downloaded. It's rare but it happens.
For example:
https://vk.com/wall-69676597_3519
the first track "Goat Of Mendes
The High Priestess" is not downloaded. Retried many times but with no success. I can play on vk though. Just for helping the developer to improve this plugin.

EDIT: I don't know how to give you more details. Try to download also this:

https://vk.com/wall-40799182_15885 (Sayyadina (Swe)2004 - Fear Gave Us Wings )
a blue progress bar start and after some seconds it stops. Nothing downloaded.
and as I wrote before:
https://vk.com/wall-69676597_3519 (Now none of the tracks are downloaded. I think VK modified something)