Good progression system games are hard to come by, this one is decent (some performance issues when you start to go fast). But the worst thing is that it is too easy/short, and there's nothing to do when you 'win', I beat it in one sitting. If anyone needs tips here are spoilers: the final hull upgrade to 90 degrees is your top priority, once you get to the red layer you can get billions easily. Too bad that 1 billion can buy every upgrade and is pointless to get money after that, though. Takes a lot of fun out of it. Potential here and with higher goals could be 5 stars.