The first Witcher was a great game, but I returned to it recently and it's showing its age. If you want to learn more about Geralt's origins but can't take the rough edges then you're in luck, because you can now play through its prologue in The Witcher 3's engine thanks to a fan-made mod.
Witcher 1 Prologue Remastered does exactly what it says on the tin, recreating the opening hour of Geralt's first outing with all the visual and mechanical excellence we've come to expect from CD Projekt Red. It's not perfect (it's basically a complete recreation in the Witcher 3, and some things don't translate directly), but it looks pretty darn good.
The trailer is above but if you don't mind story spoilers then someone has uploaded a full 50-minute play through. If you're not sure whether to download it, then watch a couple of minutes first:
Click here for installation instructions—you're going to need to remove all other mods from The Witcher 3 before you can play it.
And before you ask, no, the modders aren't planning a full remake of The Witcher in the third game's engine. From reading the discussion on the prologue mod's page it sounds like it's impossible to do with the modding tools that CD Projekt Red has provided. Making this prologue took nearly a year on its own.
If you get drawn into the story, you can buy the first game on GOG for less than $2 right now.