1: That explains a lot. That said, at the start there were some of those weak worm-things, but those eventually disappeared. Somehow I don't think I'll get that far again after the update. Also, I never did quit, I just got bored after playing for literally hundreds of waves, and it was getting very laggy.
2: Yes. There were times both loading enemies (which would sometimes not spawn for a while) and during gameplay that the game would stop responding.
3: Msi gaming laptop with 10th gen core i5 CPU and Nvidia Geforce GTX graphics card. Don't know the exact specs, but I might be able to get them.
EDIT: I just noticed that BETA0.20 is the latest version, so you may want to review that code that makes it progressively harder. Also, with a fully upgraded engineer, I just used the laser sighted crossbow as my main weapon and would whip out the machine gun and/or spam turrets when things got dicey.