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Looks like a small local computer shop. My guess is lateq experienced some f***-up on their part and vented with a happy song sarcastically thanking them for a good game. Or it was the opposite and he was genuinely happy but you know, Finns.
Would it be too simple to ost this question on his artist page?
Again, I don't have facts but that sounds unlikely. GG as in "good game" definitely came from online gaming but in some circles it became a meme and crossed over to other activities and social interaction where it was mainly used sarcastically, roughly around the time the mod was uploaded to TMA.