Layout is good. Everything is balanced. The players with less gems get more oil derricks. There are enough gems to build a base and a large army. There's a large Island in the middle with a base on it which you can capture.
Every player has it's base on an island that's connected to the middle island by a bridge.
But the two players to the left have to share 1 island. Also excellent for teamgames. You can build a good defense for your main base and meanwhile make money by capturing oil derricks and build more ore refineries. Then build a large army and destroy your enemy. Very much fun.