- Use 100 batteries.
- You changed batteries 100 times.
In order to receive this achievement, you must collect and use 100 batteries in the course of the game.
The easiest and quickest way to do this is when you feel you are close to the end of the mission, use all your batteries.
Another option is to make use of battery resupply points; if you are already at maximum carrying capacity, and batteries are still available, simply use of any excess batteries you possess. In general, the player should try to use batteries as liberally as possible, while still leaving yourself with enough batteries to complete the level.