When launching a rocket from the RPG, it will usually not detonate on impact but fly to the laser dot and just hover there in the air. This makes military vehicles more difficult to destroy, as the only alternative is the tau cannon. The emplaced TOW missile launcher (is there just one?) is worse, because its missiles will never detonate. Instead, they spin in circles at the tank or get lodged in the ground. But the biggest problem is the mortar on the water tower at the end of Surface Tension. I am unable to proceed because the missile passes right through solid objects, even the ground, without exploding. So, I can neither kill the Garg nor get through the wall. Has anyone else experienced this or have an idea for fixing it?
I experienced that too. Just restart the game or retry the map again. It’s like physics has problems there. Do objects float like they’re on water?
Yes, but only in Surface Tension, and even then it only seemed to start when you encounter the Osprey. I couldn’t say for sure if that’s when the trouble with the RPG started, because at first I thought the Apaches were shooting down the rockets like the gunships in HL2 did. I’ll try reloading the maps, and if that doesn’t work I’ll restart Surface Tension. Did you eventually get to the next level?
I only experienced it when I put the sentry at the start of that map on battle with the first set of marines with. The sentry will sink somehow. I dunno why. It will mess physics and the RPG starts to malfunction. When laser-guided it doesn’t stop and can’t reload it anymore. That glitch I think affected the next maps because physics is messed up. I experienced it the second time when I installed an alpha version of Surface Tension Uncut but I thought Text’s maps was the problem but actually it’s the map before that.
For me it always seems to fix itself after I move the mouse. (the missile will go in circles until I move the mouse, then it detonates) never experienced floating props or missiles going through solid objects.
The weird thing is that the game never even crashes, I mean it’s supposed to crash, it crashed 3 times on a developer play-through video, but I finished it 7 times without a single crash. I guess Source likes my PC.
Hecatomb, I’ve had this exact problem, too.
The rockets hovering in the air were not too serious a problem; I would press the secondary Fire button to have them explode, mostly without issue (but indeed, this is wasted ammunition 
).
I got really frustrated when airstrike missiles were going right through Garg, disallowing me to proceed in the game. > 
Upon researching the forum threads, I’m hoping this is related to
“Faulty Windows Update “KB2735855” can lead to issues!”
and I’m following instructions therein to hopefully resolve this problem (as well as other graphical, non-critical artifacts). :meh:
I haven’t had the issue with RPG rockets, but I’ve definitely experienced the intangible mortars. FWIW, I have Surface Tension Uncut installed, and I also noticed the same behaviour with frag grenades - When I tossed them, they’d simply clip right through the ground.
Restarting the game fixed it, if I recall, but still a really odd and annoying bug.
As a follow-up, I’m happy to report the solution below resolved the problem of
killing Gargantua (on my first try… which proves “it wasn’t me.” )
However, unfortunately, the other graphical artifacts still remained. I’ll post to the appropriate thread for that.