Honestly, your reassurances don't really say "Half-Life is possible in VR", they say "a Half-Life themed shooting gallery is possible in VR". The first game's tagline is "run, think, shoot, live". The games put you in the shoes of Gordon Freeman and send you on an interrupted, interconnected, mostly on-foot journey through a linear environment with some small puzzles, a lot of airvents, a fair amount of climbing and plenty of underwater sections. All of that is difficult to recreate in VR without major changes at the very least. Imagine the distances you walk in these games and now imagine having to move slow as hell through them.
I think Boneworks actually illustrates this the best - movement is slow, the main hook of the game so far is that you can use the Knuckles controllers for more precise actions with guns (with the obvious drawback that manually aiming and reloading and such will get tiresome in a full game), the environments are pretty wide to accommodate the inherent cumbersomeness of movement in VR and in general there's absolutely no speed to anything. It's slow and methodical. In other words, it's not Half-Life in the slightest. HL isn't a methodical, realistic shooter where you need to be able to flip a table on its side for cover, shoot around corners or sneak around to avoid being detected, but that's exactly what VR first person shooters seem to be going for out of necessity - fast movement and mobility just doesn't work.
