I bought the game through BMT Micro a long while ago, around 2012 and when Steam early access came out, I was supposed to receive a Steam Key but never did :/ I have my receipt and everything needed for my proof of purchase. Hope somebody can help, thanks.

^I was going to use this info quote here to help, but that's if you have it on Desura. For the super early BMT Micro, I personally don't know. But I am sure they'll be here to answer soon if this info is useless to you.
If you haven't played since the super early days then: MAN You are in for a surprise!

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Please send me an e-mail at pasi.kainiemi@modulaatio.com, the e-mail address or name used to make the purchase in BMTMicro is good enough proof of purchase to get the Steam key.