I really enjoyed this game back when, and replayed it a couple of years ago. Very unique RTS mechanics and engine, I’m excited to see this open sourced!

Perimeter had several weird gimmicks. Bases must be built on terrain that has been flattened with a terriforming tool (voxel/heighmap manipulation of the landscape is part of the game.) The titular permiter is an energy shield that you can put up around your entire base. There’s also only 3 basic units, but units can be fused together (and separated back out) to make more advanced units on the fly.

The terraforming-as-war approach is neat and I’ve always been surprised that more games don’t try to incorporate similar mechanics. The multi-units are interesting but to me suffer a similar issue as games with many guns but only one kind of ammo. By the time you’ve decided to switch tactics, you might already be too low on basic units of one type to change into what you need.