I love the series, but this game by far one of the most buggy game I've ever played on my gaming history. I hope the producer will consider to fix it :)
I found an idea of beating gregor as a biological..... if you are a poison user, equip everything that offers high poison piercing. Equip out your corrosion, envenom, reform(just in case something bad happens), anesthetic, infect, toxicant form, and max out the passive acidic blood skill.You can place whatever skill you want at the last skill combat bar. After that, use all your poison skills to the gregor(it is best if you put on the toxicant form).
When I think I had a good defense, there's a mobile artillery blitz wave, so I caleld my sig. After that, a panzerkampfwagen blitz came... what brutality...