Boring. No balance.
Either you max out archers and just turtle it out, or you just abuse Norman cavalry.
Knights + charge + any unit not in a shield wall = utter unit elimination.
Splitting enemies split through your towers only if you don't put them next to each other. If you put them at a diagonal, then they can split through your towers.
For anyone having trouble with the survival badge, just triple kick into an enemy, then kick him. It'll freeze the enemy unit until a different race comes over. They'll kill each other.