You know Legacy Weapons' original Sand Castle Wars map? This is a largely improved version with lots of new player controlled units and spawn, way less bugs, more balanced units and more strategies possible. Version 2.0 now features multispawns and a few other gadgets.

If you don't know it, try it!
You and your team have to balance building up economy and spawn.
Either rush your enemy with a strong builder unit and some units or wait until you have spawned a large army possibly including hero units (100 of a kind).
There are many ways to disrupt your enemy's gameplay.
Armies are auto attacking so you have to build gates to gather an army or defensive position. Holding and defending those gates is as important as to open them in the right moment.
Game time may vary from 5 to over 90 minutes.