Apparently, explosion sprites cannot be overwritten without access to the engine itself, which is a bummer. I have three options now:

1) Remove the ability to draw its explosion sprite from the default explosion and instead spawn the sprite myself at the same position. Sound also needs to be set to silence, that should be possible, which means I'd be able to spawn my own sound and play it. But - there must be a reason why explosions are this way, and my best guess is because of performance. However, nowadays performance should be no real issue for HL anymore on modern computers, so I suppose this couldn't hurt to try.

2) This is a Hack: Prepare three different sprites (explode_hq1, hq2_hq3) and whenever the player spawns, overwrite explode.spr with the sprite that fits the current map. This is probably not possible because the explode.spr gets cached when starting a map or something, but it could work, even if it's a little insane. :D

3) Get access to the engine and change it that way. I still haven't heard back from Valve, but I will contact them again once this project is in a more of a complete state, so I can say that it's ready to go standalone. If that doesn't work out, I'll just release it as a HL mod anyway, but if 1) and 2) don't work, this could be the only option left to change the color of the explosions. And I might have to use the default ones (or grayscale, but that would just look like regular steam clouds).

Getting access to the engine might also help improve the sound quality by higher quality wav files (if that's possible). I'm not certain how it's all interwoven, but it can't hurt to see if things like that are possible as soon as I get the sourcecode.

Anyway, I could test solution number one, but I decided to fix some easy issues for now to clear my head a little and deflate the issues list.

There were four issues in hq2_7, so I went ahead and fixed all of them:

1) The curves after falling down a hole (after pressing "exit" in the music maker section) looked super ugly and had weird cracks in them.

And here's why, this is what it looked like in Hammer:

Some random off-the-grid carving going on there, which HL can't handle (and just does whatever it wants with it). Anyway, now it looks like this:

Using my patent-pending technique (not really) that I already used to make holes in the walls in the Somos fight of HQ3, I got rid of the gaps and now it's nice 'n clean (and nobody will notice the difference xD).

2) The sounds after pressing "exit" didn't align, still need to do some testing though. Not sure why the music goes out of sync, but it should basically be fixed.

3) The HEV suits in the easter egg room looked the wrong way (only one side of the room). This has been bugging me for years. xD

4) The "exit" sign looked stretched.

And that's it for today! I'm going to continue fixing smaller issues to get rid of the noise, then go return to tackle The Bigger Fish™.