Overkill 3 Codes are used to get free stuff and discounts on unlocked equipment. To find the code entry area you’ll have to visit the settings from Camp. Once in there for the first time you’ll be prompted with a free gun offer by pre-registering at OverKill3.com. You’ll have to have an internet connection to access the area.
Visit the Overkill 3 Wiki Guide for more related info.
I hope you didn’t spend medal points on the MP5 cause that’s the weapons you get for free by registering. To get yours you’ll have to go to the OverKill3.com blog and scroll all the way to the bottom. Now just add an email address and check you inbox for the promo code. Now go back to the settings, enter it in and your good to go. I’m sure that once it’s used it wont work for anyone else.
Im sure your wondering how to get more after that one right? Usually promo and referral codes are used for advertising to people who aren’t playing the game. They can often promote them on developer social media like the Craneballs Facebook page. But more often than not they are used to pull folk in who are playing others games.
You could also search for Overkill 3 Codes on YouTube. The only downsides to this is the large amount of trash you might be searching through and the possibility of ending up on the weird side of YouTube.
Playing other games by the developers can also be a good way to get some bonus offers especially past titles like OverKill 1 and 2. Firing them up might reveal offers letting you know about the new app just released. In the last installment they had Black Market codes though so far I have yet to see any. Check back in the near future for any updates.
Other than that I’m plum out of ideas. If there is anything that you would like to add that might help others feel free to mention it in the comment below. In the mean time check out some Tips and Tricks which could help shed some light on things.