I remember, during the testing of this campaign back in 2007, I recommended several enhancements to the author – he incorporated only a small portion of those recommendations into his creation.
At that time, it also seemed to me that there wasn't enough hardcore difficulty – which, however, is now indirectly confirmed in his message by overvlad_33.
I played through it with a hero using the EVA mod. Mega AI mode was activated. The difficulty was extreme.