Wanted to make sure people knew not to use the “Boomstick” skull on Halo Wars mission 4 (that level where you save the civilian transports, also the level for the achievement for saving adam) If that skull is active the civilians count as “non-player units” and 5% will blow-up upon entering it. I don’t recall this being a problem last year when I went through it, but just noticed it helping my little brother co-op the campaign for some achievements. I’m not making it up, did the mission 2 more times just to double check it.
Tested on Normal difficulty on co-op (system-link) with all the Beneficial Skulls active (esp. Boomstick).