Originally found by WindedCone on the PS2 version of Half-Life, with YaLTeR then discovering that it works on Blue Shift’s WON version (which carried over some stuff from the originally intended Dreamcast version, hence the testing). I decided to go ahead and test it out on Half-Life and discovered that it works there too.
This trick only works on very early versions of the game. The latest one I could get up and running that has this trick was 18.104.22.168, released in 1999. It’s commonly used in Source speedruns and this particular movement is most similar to Half-Life 2’s ‘Old Engine’, moving you upwards after you crouch, save and then load.
The only methods of getting OoB (out of bounds) that we know of right now are via “leaks” in the map, or through triggerdelaying and then getting stuck in a wall. I tried getting stuck with snarks and tripmines and couldn’t replicate the clipping.
We haven’t found a confirmed use for this yet, but I’m hoping by sharing this video others will be able to look into possible routes.
EDIT: Confirmed working in Half-Life and Blue Shift, however 22.214.171.124 doesn’t seem to be mod-compatible, so we would need to find a later version to find out if it works in Opposing Force. Unfortunately the version I’ve been using currently is the only one I could get working that has this trick. I can confirm it doesn’t work in Gunman Chronicles (which makes sense since it was released in 2000).