puh...:
1) lags really too much
2) if you pause the game cooling of the weapon keeps on
3) if you fire a bunch of mg bullets and switch to cannon before they impact they count in the moment of the impact as greande
4) could insert some autofire option
5) split the upgrade from the mg to burst and damage
6)... etc.
BUT - I never programed a game or something. So its for sure easy to tell whats missing and perhaps difficult to realise everting. Thanks for your work!
some things you could add/change:
1. some sound
2. a tutorial
3. statistic of dwellers needs
4. more upgrades for the stores (etc.), i have so many stores for a few citizens
(5. potential upgrades could be linked to your level)
6. a puse button
7. several entrances for a building
so - in my opinion the game has great potential. like the idea very much!
 "Tank Crusader"){kind=icon}
 "Imperium 5"){kind=icon}
 "Hobo Business"){kind=icon}
 "Destination Kepler"){kind=icon}
 "Idle Raiders"){kind=icon}
 "Obliterate Everything 3"){kind=icon}
 "Glean 2 Preview"){kind=icon}
 "Mutants! Defense"){kind=icon}
 "Shoot Them All"){kind=icon}
 "Build & Destroy Space (update)"){kind=icon}
 "Defend Position"){kind=icon}
 "Air Empire - Build and Maintain"){kind=icon}
Tips noted ;)