Nice fun short incremental game that becomes more of a puzzle due to the time limit. Well done!
Few suggestions:
- A "greyed-out button" typically signals that it cannot be clicked. So I would suggest changing the used colors.
- I think the tutorial text was not needed. A level with only a town hall, one place to fit it, and upgrading it, before the time runs out, should be sufficient to learn the game.
- Maybe keep the game going until the timer runs to 0.00. Then give the player x amount of stars out of 3 depending on how much points he or she managed to get before the time ran out.