For me it was back when it was still called Dyson, when the very first demo was covered by indie news outlets, the demo with just the asteroid belt. Months later I saw an updated version of the demo was released and played it, version 1.08, the one with 5 levels and the crazy aggressive AI, in the asteroid belt level, I remember that by the time I had conquered half of the map, the AI that started on the opposite side of the map had conquered the other half, it was such an epic battle, it was after that mission that I knew this game was a must buy.
Then version 1.20 came and AI seemed different, weaker, in the asteroid belt level enemies barely conquered more than 3 asteroids, but I was still giving the commercial version a chance since some fan levels were as frantic as that epic battle I had the pleasure to play in v1.08.
And I don't regret it since an epic battle, one that dwarfed just every other battles I had in any version of that game, happened in the Dark Matter version of Colliding Worlds, where I screwed up 10 minutes from the start, lost tons of seedlings, let the enemies gain the edge. After 25 minutes I was back to 4 asteroids, each of the four enemies that surrounded me had much more, a part of me was willing to restart the mission from scratch, a bigger part of me knew if I did that this humiliating defeat would stains my gaming record for the rest of my life. I didn't give up, it took me more than 2 hours, partly because I helped my 4 enemies when they were attacked because I wanted that it was me and nobody else who'd deliver them the death blow, but I did it, and it was great.