Year of the Dragon, a Half-Life mod that replaces Gordan Freeman with Spyro the Dragon, has finally entered early access. You can download and play the Office Complex demo over on ModDB and glide, charge, and breath fire all over the early-game Half-Life level as a talking cartoon dragon instead of a boring MIT graduate.
While modder Magic_Nipples (nice) isn't necessarily going to recreate the entirety of Half-Life to work with Spyro's original moveset, they're at least making it possible for others, bringing the former PlayStation icon to the GoldSrc and Xash3D engines for modders to play around with.
You'll need Half-Life to give it a go, of course, and not all controllers are compatible quite yet, but what's there looks like a near perfect recreation of the original Spyro. Give it a go and let us know how it feels to finally play Half-Life as it was always meant to be.