Stats Upgrade

Winston has 3 stats: 

Health: That allows us to survive more hits from enemies.  Max upgrades: 5 

Damage: Our hits deal more damage to enemies. Max Upgrades: 5

Speed: Makes us more faster to outmaneuver enemies. Max Upgrades 5.

When can i upgrade my stats?

At the end of every wave, it will show us a screen to upgrade our stats.

How can we Upgrade our stats?

We can upgrade our stats by killing enemies, when we kill enemies they have 30% chance to drop coins with this coins we can  upgrade our stats.