Let us pre-order already, Denis -- you need to let people test this game with a wide variety of distros and hardware combinations before release, so you have a chance to iron out any bugs before you start moving your development team off your released game to another project.
I'm willing to give you full retail price if you'll just let me test it and provide you with what are likely to be informative bug reports on any problems I had. The game looks fantastic and I am ready to give you my money, even if the game I initially download is disappointing in terms of completeness or bugs. I want to help. You're taking the Linux plunge; you deserve it.
Thank you for your kind words! We do realize that QA and distros compliance is very important, that's why we do a lot of this work in-house. Anyway we would be happy to have more feedback after launching early access to the game.
BTW, pre-ordering is really very close, at the moment we are finalizing payment gateway integration.