I love the idea and the game.

Suggestions for improvements:
1) Balance - the only expensive stat is Yield. I reached the megapolis 72 level and it's the only one stat that is not maxed yet. Other stats are easy to max. The game becomes plain after Megapolis 20 level - I just launch bomb and move on to the next level.
2) Stats - you introduce new stats along with the game progress but then you cut the majority of it when Megapolis levels start. Why?
3) Level design - it would be interesting to search for the weak point of the city. For now you merely aim the city center and progress the game.
4) UI - all your stats have a bar indicating how many times you can upgrade it except for the Yield. At first I thought it was a bug that the bar wasn't filling up. Then I realized that that was because there were far more upgrades available for this very stat.

Generally I love everything up to the Megapolis levels.

Congratulations with the launch!