Quite good fun this, so long as your security settings don't automatically delete your browsing history between sessions. Build up your fighters and upgrade weapons and skills to gain levels and access to better arenas.
It's a good idea to have at least one fighter heavily armoured and with a shield, because in higher levels they can also shield their team-mates from attacks, leaving those all-out offence dudes to smash your opponents about with impunity.
Another tip is to look at your opponent and choose where to strike them depending on what they're armed with and how much armour they have in the various locations.
"You're a big man, but you're in bad shape. With me, it's a full time job." – Lt. Bromhead to Prince Dabulamanzi before the Battle of Rorke's Drift.