Hello Troopers!
We have received many messages regarding problems with one mission that asked to do a 20 kills combo. It was indeed not working correctly, and we have updated the game to work as it should: not a 20 kills combo, but 20 kill combos.
You have to sum up 20 kill combos while playing this stage, instead of the impossible 20 kills combo.
If you find any other thing that is not working as it should, keep telling us on the forums and we will solve it as soon as possible!
Godspeed and live the resistance!