Was fun! I really liked how the idea of the game getting harder as your bounty went up, and doing things to try to increase that bounty. It was a bit repetitive with damage requirements being so high, and the upgrades didn't quite scale with it. The impact of doing extra damage is also lost when the enemy's HP also scales up. I'd probably recommend some damage numbers popping up, or choosing to increase quantity of enemies rather than increase hp.
The balancing is a bit off, especially with the deadly bullets upgrade. It's as effective as 3 damage upgrades, but it also takes 3 upgrades for it to be reusable (1 deadly bullets + 2 health). I know the health upgrade said it would heal to full, but it only healed to 10 for me (after i had previously picked up the health). I wish it was an upgrade that you could equip in the beginning without health upgrades, would have been more interesting.
All in all, nice simple and fun!