too slow paced
Your money income is way too slow, or vice versa the prices on the upgrades are way too high. Your price range for stuff is like 20k - 100k and you make about 2k in a normal 'run'. I had a few bad runs where I made barely any cash, but then I had a very long and good run (at least I thought it was good). I got to the bonus level and completed it, I made it all the way to space theme and must have spend like 5 minutes on that one run. Then I look at how much cash I earned, and I got bit over 7k for it. Cheapest upgrade being 20k for the launcher so I was still miles away. I closed the game at this point.
Seriously how much time you expect us to spend on the game before we can upgrade something? And I don't consider buying one grenade for 7k worth the money as the nades were pretty common. I'm not going to spend half an hour on this simple game so that I can upgrade my initial launch to be a bit higher. You need to think that people like to upgrade stuff, and this approach where you put the upgrades far far away is not the way to go.
The gameplay is very simple and thus gets boring pretty quickly. The upgrades would have spiced it up a bit but since you can't get them in reasonable time, this game ends up being just another boring game.