rhoadblock achievement won't unlock
Playing on level 2 of Heart of Gold. I am pretty certain no enemy units slipped past me and the gateway and nearby road were still covered by the fog of war. But when I completed the mission, I was not awarded the rhoadblock achievement. I had unlocked all 12 artifacts.
Game Version:
Steam Public
Platform:
Windows
I've just played the level now and was able to get the achievement. I think you probably just let a unit past without realising.
The Log also shows that the game didn't even attempt to unlock the achievement, so it is very unlikely that you killed all the empire units.