You call them having big counterattacks cheating?
How about us having goddamn powerfull spell cards.
Also you should never rate a game based on lag, they can't help it but you can.
Billtog your computer is the problem, not the game, my PC can easily handle all of this, even when a counterattack of at least 200 guys are coming towards me.
I only needed Witch, Phantom armors, mermaids, centaurs and dwarf engineers for CoT5, don't use succubusses or cannons because they will launch the invincible gobbo towards your castle.
For the cave of trials lvl 5 you just need a whole lot of ranged units and goblins ( MERMAID'S ARE A MUST! ) and when you start bashing the castle use the invincibility spell card when the counterattack starts.