Ok, there are some levels that appear to be decent enough, but jesus does the difficulty curve go up from "somewhat challenging" to "lol you are fucked!"
I am talking about "Testifilim" and "Second Euphine War". Just when you are recovering from the last wave of hero offensives and are pushing deep into rival keeper territory, a massive hero army jumps in and wipes you out, while in the case of the latter, there is a tunneller that seems to be an instant-lose condition upon death (even though you have imps).
As well as that, there is an odd scripting quirk (as in MASSIVE spaces in lines of script, making it impossible to read).