Happy Tree Friends False Alarm

To get this Achievement of evil (your and the games) you need to complete each of the three level in a Zone with each friend at 25% or less health. Their health turns blue when you reach 25%. The level I did it on was the Power plant using the radiation at the end of each level to evenly bring their health down to the blue and the letting them finish their walk.

The best thing to do is keep them from taking any damage until you reach the radiation at the end of the levels so that they all have close to the same health. Then just expose them to it until they turn blue. Some times they don't all lose health at the same rate so just freeze any that don't take enough damage and lead the rest to the end before going back to deal with the ones that need to be dealt more damage.

This has to be done in one sitting, which means you have start the zone and go through all three levels in one play-through. No exiting the zone. It IS okay to replay the level in case one gets through with too much health or you accidentally kill one or run out of time.