This is not really a cheat but I prefer staying on after the levels are finished to possess my minions.
Anyway, here's some advice on creatures:
Fly:Very weak. It is an exellent explorer, and it tends to keep getting into battles if you tunnel into a new area.
Beetle:Weak, but not as weak as the fly. It can't do anything like walk across lava or fly. Just a basic so-so.
Demon Spawn:Good fighters but drain away your money like a sponge.
Dragons:Tough fighters but slow and lumbering.
Warlocks:They are greedy so as soon as it's pay day they will be zooming off like a rocket for their money.
They are useful as they will research for you.
Bile demons:Research for you as well. They tend to get very annoyed if you don't cough up money.
Spiders:It may not look like it, but it is a good fighter. At level 5 or 6, they will start to learn how to freeze things, so it's a good idea to start training them as soon as you get them.
They will kill flys as easily as snapping an elastic band.
Vampires:Hate Warlocks. They are like the spider, because they are stonger than warlocks.
Skeletons:Only join you if a hero dies in the prison.
They can cast magic spells, mind, so always try to get these.
Dark Mistress: Exellent fighter. They will cast spells and do whatever they can to win a battle. They will always die if you slap them too much, but they love being slapped and will never leave your dungeon through slapping.
Horned Reaper: He can only keep happy if you keep getting into battles, because soon if you don't have him in a battle he will start killing your own creatures. Hates the Lord of the Land.
Imps: Worst at fighting, but you are in trouble if you don't have any imps, and you don't have any money, because spells cost money, and you can only get more through the Create Imp Spell.
They can dig out tunnels, dig out gold and bless the floor yours. They can also help your walls get stronger.
Thanks for listening, this took more than forty minutes!