Play in 1000 DarkOps games, either online or against bots. The quickest way to get this achievement, is to set up a match with the following settings:
Starting Amount: 15,000CR
When the purchase screen comes up, buy a rocket launcher. Once you have control of your character, shoot a rocket at your feet. Match will end in 10 seconds. Factoring in load times, it will take approximately 9 hours to complete 1000 games. It can be a mix of online and offline.