Played to wave 40 on Chrome without any crashing issues.
Putting overclock on Rook gives them 90 DPS each. That's pretty much the core of it. I use the double spawner on two Rooks, both hooked up to the explode on death, 2x shield thingies and overclock. Then 4x AoE missile launchers to deal with the small fries and as many longbow's as I can fit and still have enough resources.