Voxels! Remember those? Back when they were the in thing in PC games, I picked this game up on release, installed it, played a bit and then forgot about it (as I often do).
It was 'Outcast' an adventure game by a little known Belgian developer called 'Appeal', released by InfoGrames in the UK.
I went back to it a few months later, as one of those 'Oh, yeah, should finish this' moments, and then was hooked for the next couple of weeks, before I finally mastered the tricky 'shoot slow-moving bolts while riding strange alien ostrich-dinosaur' moves needed to progress.
The score was utterly gorgeous. And the freedom to explore the planet, as much as to progress the game, was quite unique at that point in time. It's been remastered ans is, of course, now available on Steam.
Sadly, the much awaited sequel never did materialise because I don't think it was that big a hit here or in the States. Pity. I'd have loved to go back to Adelpha.