I played Perimeter, OP! I loved the deranged storyline which has, as I remember it, these three ideologies battling over a some new (maybe psychically created?) realm of existence trying to escape it/perfect it. I feel like Perimeter was from a time when there was lots of RTS experimentation: Warcraft 3 with its heroes is the big one that changed the course of RTSs forever, of course, but also things like Company of Heroes/Dawn of War with its squads, Kohan (also with squads, but with more flexibility AND heroes), Maelstrom (with more terraforming), Exile, with its multiple map levels (I think there was a mech-building RTS with something similar, too).
As for an obscure game that I loved, it has to be Metal Walker. This was a Gameboy Color RPG where you played as a kid on a post-apocalyptic world who controlled a robot. You fought other robots and found element cores (air, water, and earth) that you could plug into your robot to change its form and its stats. The battles had you essentially playing pool: you'd launch your robot around the arena to bound off walls, avoid obstacles and traps, and slam into the enemy robot to deal damage. You also could scan enemy robots to get their special abilities.
