Huh... That's a hard one.
It was my childhood. I only ever got to play Chapter One, because it was what my Dad had from when he had bought it a few years before, but I loved it. I knew those levels in and out, Tyrian to Deliani. And damn if I wasn't good at them. Then, unfortunately, the computer with the game on it broke. And it was gone forever, so I thought. Almost a decade later, I looked some stuff up online, trying to buy a new copy, but couldn't find anything. Then... I stumbled upon a Tyrian fansite, offering the ENTIRE game for free, including the unpublished Chapter Five. It turned out that the company had gone bankrupt and disbanded, and one of the game's musicians was the last one out of the building. After a week of searching, he finally found the backup final version of the game that never had a chance to be released. Out of the goodness of his heart, he posted it online as freeware. And it's still good. Aaaand that's my story for the day. TNPW indulge in nostalgia, and optionally also play some Tyrian for themselves.