Damn, really far behind; mass update incoming 
First the clues:
26. Previous iteration of a game that came out on the 6/12/13.
24. Not the first game in the franchise, but it did introduce a memorable musical score to the series which has been remixed and re-used for the sequels.
23. Like Baldurs Gate but in 3D.
22. This game popularised one of the biggest franchises of the gen.
21. This game features a character who managed to get on the cover of Playboy in Poland (not the actress, the actual virtual character).
20. Features possibly the longest (or shortest if you're lucky/good) boss fight in existence.
19. An HD remake recently came to Steam, there's even a new expansion pack.
18. It was all a dream.
17. This game's spiritual successor released this year (and is now higher on the list).
