This game is a lot of fun, and has been keeping me up late at night. Initially I wasn't particularly impressed. The story was interesting but I felt there was something lacking in the style of the units and the feel of the combat (indeed I still think it is a bit weird...). I gave it a chance though, and my opinion changed after just a few levels. Because Perimeter provides something truly different - a hardcore RTS in which games are won and lost by clever placement of structures. Here your units are very much secondary to your base. This is not the only change you can expect if you consider yourself an RTS fan - this is a big game with a lot to learn. The sheer number of new gameplay mechanics compared to traditional RTS games means you are still learning new techniques 10 levels in.
If you are a fan of god games then you'll have a lot of fun building the biggest and best base possible (and taking over enemy bases!). This together with the diverse strategies, compelling storyline, and the need to beat the next level is keeping me coming back for more. The game is complicated, and at times quite hard. I've found myself searching the web for tips and turning the difficulty down to "easy", but then I was expecting another "C&C". After I got used to it... well, I was *still* searching the web for tips, but having a lot more fun! I haven't finished the game yet but I've seen enough to review it and recommend it to other GOG members. Yes, you guessed, I am stuck on a level and don't know what to do next... I'll sleep on it, and beat it tomorrow...!