Lots of room for improvement
There are few very obvious problems that MUST be fixed,
-Coins that fly out smashed buildings and land behind you cannot be picked up;
-The music duplicates every time I start a second game or any game after that.
If it was possible to make the game a little more complex, I would suggest:
-Drops other than just coins (e.g. power-ups);
-Levels, each one harder than the previous one;
-At the end of each level (see above), there should be a shop where you could buy things that assist you in the game, (e.g. armour/defense upgrades, weapon/attack upgrades, speed upgrades, health upgrades)
-Boss fights
-Option to save and load games
This may sound a little farfetched, but I imagine that the game would be so much more interesting if these suggestions were implemented into the game.