All the cheats and secret levels for When the plague came
There are a total of 5 Cheats, these are hidden buttons you can find through the game, two of which are bonus levels, the others give you more HP, more damage and stuff like that. You can find the Cheats in this locations
The first and the second are in the Weapons Upgrade menu: You click the Machine gun Icon and you will unlock the first cheat.
First and Second Cheat:
The second you should first buy the third IceGun upgrade then click it again to unlock the third cheat.
The third is in the Fortress Upgrade menu, click the Risk level text
for the other 2 you will need to wait some time, you will have to unlock the Slug Parasite and then BallBlivion Once you unlock this enemies, go to theyr profile and click theyr icon, this will send you to the secret bonus levels!