Hello,
When in killing spree missions, the destroyed bot count is upward, but the message is telling it is downward.
The more ones you destroy, the more are remaining to kill...
Regards.
Andre Felipe

Yeah, this is a known bug, and in no way Linux specific, the killing spree mission was only ever intended as a test mission for some new stuff the devs put in a while back, and will either be improved apon, or removed for a much better mission.