There we go.
1: Asha is the second to last boss in the game. Normally, after beating him, you'll find a log that rambles about how you have no chance against the final boss. You'll have to skip Asha's fight in a pacifist run...in which case the log goes on about how humiliating it is that you didn't fight him.
2: Your brother Dan gives you a trap mine and tells you to put it on a teleporter. Shortly thereafter, you find yourself in a room with teleporters spewing enemies. The obvious suggestion is to use it right there. Doing so means you won't have it to stop an ambush later in the game...with the result that Dan gets killed. Moral: never listen to Dan.
3: Robots don't count as kills, which is important for a pacifist run.
4: As is pumping health, because it means you can afford to take missiles in the face and kill things with the splash damage.
5: Would have been: "Summoning genocidal aliens might not be the best way to get rid of genocidal aliens." Moral: never listen to Dan.