Monotonous. No difference between planet one and planet seven. Idle games are fun because the number keeps increasing, but because the 'ascension mechanic' is the primary method of progression through the game, you don't actually get the feeling of runaway growth that many idle games have. The fact that each planet costs the same amount of gems to unlock means there's no benefit to unlocking them as you play; you're better off unlocking every upgrade on Earth, waiting a few moments, then clicking through all the other planets.
That said, if I understand some of the text of the planned mechanics correctly, then there's some really neat concepts here. The Space Station implies that resources from planets can be shared - which implies that you'll be able to go back to other planets you're mining on in later builds, which could make later parts of the game very interesting as massive pools of resources become available (so long as you implement things to actually do with them). The alien invasion stuff sounds interesting, though I'm curious as to whether that's planned as a randomly proccing event or a passive drain on resources. Or perhaps there's some of both.
There's a core of a really interesting idea here, but I think there's a fundamental balance issue that should be resolved before implementing the remaining features. Idle games live and die by the numbers, and this one needs its numbers adjusted.

It's an idle game that pauses when the window is not focused.