Really enjoying the game so far!
A few things I'd like to see implemented:
Ditch the timer if possible, or an alternate game mode where powerful enemies spawn more commonly as it progresses until you ultimately die.
More stats at the end such as Doggodollars acquired, total dog slaughter count.
Pickups such as health and money magnet etc
Change colour of money to green and perhaps have them 'merge' together to help w visual clutter.
Cant wait to see where it goes!