I'm beating Half-Life 1 with a SNES Controller (On Hard!)
Why? Science isn't about why, it's about WHY NOT.
The DPad is bound to WASD, and the face buttons (ABYX) are bound to looking around. Fire is Right Bumper, select is Use, long-press is Flashlight, and Start is menu, long-press is quicksave. Which I have to use A LOT.
How do I crouch? Jump? Select weapons? Left Bumber is a mode shift, which means while holding it down, the function of the face buttons switch. Left Bumper plus B is jump, A is toggle crouch, and Y n X are both weapon selection.
How does it play? Honestly not nearly as badly as you'd think. It definately takes some getting used to, but Half-Life 1 is genuinely really playable like this. Unfortuantely auto-aiming doesn't work because of the stuff I had to do to get this working properly with face buttons, so I'm entirely relient on my own skill. Which is. Not good.
Fighting with the soldiers requires a bunch of quicksave scumming, and just hoping you get lucky. More often then not, you'll leave a firefight with less then 10 HP.
I'll be happy to answer any questions you might have. This hurts my fingers. And yes, I do plan on beating the entire game like this.