All of you guys seem to make it hard. Here's a good strategy for the factions
CIS : Choose the Assault Droid and run as fast as you can to the Lighthouse, then capture it. Then if you have time run between there and the Fortress. Lay some mines so IFT-X's don't rock your entrance to the ice-caves. Quickly get back up and shoot at the AT-TE. The AAT's are great against it. There goes a Mobile CP and a lot of Reinforcments. So now that it's gone, take down any other IFT-X's. After that, snipe or go capture the Ice Caves. You will win after repeating this strategy.
Rebels : Choose a Sniper/Soldier/Wookiee/Vanguard and run to the Lighthouse. Repeat the strategy from CIS. The AT-AT is not stronger than the AT-TE, they are equal. The Combat Speeders aren't very strong, but can do damage to the thighs of the AT-AT. Once it's gone, choose the Wookiee and head for the Ice Caves. Grenade your way through and the game is yours.
Republic : The AT-TE is weak compared to AAT's. Spawn at the walker as a Jet and fly your way to the Light House. EMP shoot any Droideka's at the entrance of the Ice Caves. No real strategy here, just guns blasting and grenade explosions.
Empire : What an easy and pathetic level. Hop into the AT-AT as a pilot, and blow up turrets and speeders. Pilots will run to the turrets, and you get easy kills! If you don't get 80+ kills, be ashamed.
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