I find it kind of interesting that D&D wasn't your first pen and paper RPG and that that's true for most people in Poland. Here in the states, D&D is like a gateway drug.
I have started with hand-me-down Warhammer Fantasy Role Play 1st edition from my brother (the oldest RPG here, first one that was translated to Polish in late '80s o around that time) and in the meantime I was playing:
- Cyberpunk 2020
- Wolsung: The Steam Pulp Fantasy (original title was way better though; Wolsung: The Magic of the Age of Steam)
D&D was probably my third or fourth system overall :). It's not because of popularity, although it's not the most played one here, but because D&D books are fucking expensive when compared to some of the other RPGs. Admittedly, they have some of the best production quality out there, but for a price of 3.5 PHB alone, back when it was new, you could buy Neuroshima core rulebook and one flavor book (literally, very low on mechanics but about 70 page worth of scenario inspirations in stories and rumors you can find during your adventures).
These are not the only games I know, but it's a good selection of ones really popular here aside of recent surge of Dark Heresy and similar 40k games.
I'll try working on the English version of the setting and start sharing it here, but after reading it last night myself I have to say that it is more likely to be a major rewrite than just translation. Let's say that idea started when I was about 13-14 and you can likely guess how that might look. While I pride myself to have no Mary Sues in the setting, I have a hard time finding a page where there is nothing for which I don't want to travel back in time and slap my younger self :P.