I can't understand, why GOG sells the game at 19,99$, while its straight competitor STEAM has it at only 9,99€ or ~13$ considering a EUR/USD ratio of 1,3! Even worst STEAM does not indicate that it has any promo running on the game, which means that this is its standard price. So STEAM is 35% cheaper!!!! And till now I had the impression that low prices was GOG's major advantage over STEAM. It seems, things have changed!

Well, to be honest, Steam has different prices in different regions. Somewhere it's 10-13$ and somewhere double that. On the other hand, GOG offers one price for everybody.

Actually, GOG's major advantage over Steam is the lack of DRM. The reason games can be more expensive on GOG is because GOG uses the same prices for everyone, as opposite to Steam's regional pricing. However, a lot of people seem to be willing to wait for a sale on GOG and get the DRM-free version of the game, rather then buy it on Steam. Some actually buy a GOG copy after they've already bought a Steam one.

One thing I know and it is the basic market rule as well is that if you want to take clients from your competitors you owe to have competitive prices. Especially, when your competitor has bigger market share. If you do not do this you are doomed!!! The rest is just words to say!

What do you mean by "if you don't believe you're jumping to conclusion", I don't quite understand!
Anyway, I just made a comment on the price difference. As I learned from other forum members STEAM has different prices depending on the location you use to access their platform. For Greece, Brazil and many other places it has set the price to ~13$. For USA the price is 20$, etc.
Personally, speaking, I do not even have a steam account and I prefer GOG for my purchases.
However I cannot close the eyes to the fact that for us, here in Greece, where GDP per capital is almost half of that of USA, the price is the same. Probably GOG, should adopt a more flexible pricing scheme as well, or at least have better prices than STEAM's average, which means that if Steam sells 20$ in the US then GOG should sell at 15$ for example.

That's a valid concern, but the whole idea behind GOG is one price, no DRM. There's the business side which you can not simply ignore and make it $15 on launch.

on steam is also soundtrack. why there is no soundtrack?

I believe the soundtrack is sold separately as another bundle for about 25$ and is not part of the actual base game package.

from Steam:
The Night of the Rabbit Premium Edition 12,49€
Includes Original Soundtrack (41 tracks), 8 audio books (160 minutes total running time) and a wonderful game comic by Olga Andriyenko.

There's 8 audio books included in the GOG version of this game by the way. You just need to find them, although it's not hard.

And the entire soundtrack can be listened to on Youtube here as an alternative. http://www.youtube.com/watch?v=OA-K7umU2_U&list=PL-NNKmznDOY5ZtjCMfHb_PCaiJkvW9HZZ

I'd rather have the Special Edition as well, but it's part of GOG's policy to not offer multiple versions of the same game.

For me GOG's one price is often the reason of purchase. North European price for The Night of the Rabbit is 19,99€ on Steam and premium edition is 25,99€. So, for me GOG's price is cheapest and there was Indie promo today, so this was even cheaper than normally.

also prefer GOG - and would buy anything i already have on steam if it appears on GOG - and wouldn't buy steam version of GOG game - never! BUT WOULD LIKE MUCH TO HAVE NIGHT OF THE RABBIT SOUNDTRACK IN GOG PACKAGE...please