I have the same problem, only it is not playable on wave 18. I have only 8 gb of ram.

Wave 17 for me

did anyone find an answer to that ? I have the same problem at wave18 quality very low (with gtx 970 and 32Go of Ram...

No currently there is no solution or workaround. We will just have to wait until author releases fix.

T'would be nice if somebody in the modding community created their namesake with the intent to remove all of the bodies, yes. However, I don't think that will happen for some time, as it could potentially break the game, what with sectoids and their habits being what they are.

haven't played this mod myself yet, but I've been keeping my eye on it for when I finish my current playthrough so bear with me if I am asking stupid questions; from the sounds of things, do bodies never get cleared from that map? From the few videos I've seen it's just persistant gameplay and never goes back to the Avenger for anything. This is the culprit right here but since I haven't played with the Xcom 2 modkit I really can't comment too much on what is a viable solution. You'll either need to find a way to remove bodies after 'X' turns if such a thing is possible in the tool kit, and if not then every 5 waves or so you'll have to do a 'pause' where the game "completes" the current mission. You'd head back to the avenger, spend resources to gear up again, then it drops you back into the previous map with new pods. The latter fix honestly seems 10x harder to an outsider who deals more with actual code than mod code because of all the things you'd have to track as well as all the hooks you'd have to handle so that that game doesn't actually progress like in vanilla compared to just deallocating a bunch of old memory.

Remeber that whole 'caps lock to skip loading screen' thing? During those post mission debriefing screens is when the game engine would do its garbage collecting and properly free up all the memory it requested. Without those instances of cleanup the game will just keep requesting more and more from the free store until eventually you run out and it starts overflowing to scratch space causing terrible slowdowns.

the bodies do get removed on the latest version, but on the upcoming update I found even more stuffs that can cause performance issues and attempted to fix them, in my testing I can kill 24 pods of enemies (8 waves worth) without dropping performance so things might look a lot better soon. The update is not on the workshop yet but if you are interested in testing for bugs you can get it from here https://github.com/bountygiver/WaveCOM/releases/tag/release-bg_update4-preview

I still have the problem. I'm wave 15-16. When I was playins, it was going slower and slower, but was still playable.
But when I take my save back, it becomes very, very, very slow.
Can't play anymore. I have a 970, i5 2500k and 8 Go Ram.
Tried to reboot, but no effect..

Sorry to Necro here but iirc this memory leak is an inherrent problem with Xcom 2 bullet rendering. Basically the devs never expected anyone to remain on the map for that long, so whenever bullets get cast they are sort of summoned objects that hover in the outside edges of the map. I dont think this is a mod author issue but more of a "the devs never expected anyone to use the game this way" issue