ENSURE YOU WATCH THE VIDEO AND SAVE BEFORE ENTERING THE ROOM WITH THE IMPS!! This achievement gave me quite a few issues. You need to weaken two imps and line them up correctly for a final shogun blast. The easiest place to do this is Chapter 2 in Administration Lobby - Alpha Labs 2. If you happen to mess up and kill one of them while weakening them, just reload your save. Here is a video to help,
Credit to R3LAPZE for the video.