See https://imgur.com/a/1q7Wg for a full explanation. It's not clear from the album, but the entities also blocked my movement where they were packed most densely.

Note, I only noticed these because they prevent building at their location, but if you were to somehow make it possible to build on top of these entities, that still wouldn't really solve the problem. The entities need to be cleaned up.

I had some free time this weekend and was able to fix this myself. The sound trigger entities persisted because their prototype was a SimpleEntity; changing it to Explosion apparently causes the entities to be destroyed after their animation and sound finish.

I also made a few other fixes, in descending order of importance:

• Don't overwrite the entire prototype of artillery cannons and ammo just to add extra effects. The inherent problems of that approach are obvious.
• The sound entities (as well as the sound trigger entities) should be of the Explosion type. AFAICT this causes the sounds to finish playing if you load from, say, an auto-save that happened half-way through. Since the sounds are the whole point of this mod, I thought it would be a nice enhancement.
• Better organization: new prototypes should be created in data.lua, modifications of existing prototypes go in data-updates.lua.

The whole patch series is here: https://www.dropbox.com/sh/fx8q5j4pgrskycy/AADNPBAdlC51UNYomJtkOJIDa?dl=0

Hello,

Thanks a lot for the extensive bug report and provided fixes ! I've integrated most of your patches and pushed a new version.

However about the sound type to explosion type I couldn't see any difference while testing (even saving / load during an explosions sound). So I've kept the sound type as it seems much lighter (code wise at least).

Let me know if it all works good for you too and thanks again for your help.