Here is the full list of all 9 Machine With a Big Gun achievements.
kknd
krush kill 'n' destroy
krush kill 'n' destroy3
krush kill 'n' destroy4
krush kill 'n' destroy5
krush kill 'n' destroy6
krush kill 'n' destroy7
krush kill 'n' destroy8
krush kill 'n' destroy9