I noticed that some players who have already tried Grandmaster's Revenge
can't figure out how to be efficient and defeat enemies. There are many different tips in the game: Tutorial campaign, Bonusopedia, Archivist Agnotius with his tips and more. It is enough to use any source and it will be much easier and clearer to play. The game is not casual, it has a lot of game mechanics that are presented to the player in stages, deal with them and you should like it.
In the video, I play the free demo on Steam and show how to be a problem for the myriad hordes of Blackwood.