Hi. While most achievements in this game can easily be achieved just by playing the game on every campaign, there are some achievements that can be "missable" in the Battle of the Bulge. This guide will be focused directly on that.

Please check out the artist of the guide picture on Twitter.[x.com]

The achievements to be most careful about missing are:
Mortar Command
Call in heavy mortar artillery 5 times
KABOOM!*
Kill an enemy tank using an anti-tank grenade
Held The Line*
Complete a defensive objective

This guide will cover these three achievements.

Two achievements can be easily unlocked in one mission. It is the second mission in the Bulge Campaign; Cross Roads

This achievement is the easiest out of the three.

Simply unlock the heavy mortar upgrade by getting the two upgrades highlighted, then deploy an officer. Select the officer and select and use the command 5 times, after the battle is over, you will have the achievement.

As a prerequisite for this achievement, you must have anti-tank grenades unlocked.
The earliest mission you can achieve this is on Cross Roads, the second mission in the campaign.

When you reach the second part of the battle, a enemy tank will spawn on the bottom lane shortly. Use infantry with anti-tank grenades to eliminate the tank. If you haven't unlocked the achievement Hold The Line, hold off on spamming too much infantry.

The earliest you can get this achievement is by the second mission in the Bulge campaign, Cross Road. Upon eliminating all the targets on the crossroad, the third stage of the battle will commence. You will be instructed to hold the line for two minutes.
Avoid spamming infantry and avoid spamming anti-tank teams, use officers or infantry to destroy enemy tanks.

Upon reaching ~0:20 seconds left on the clock, you will be reinforced by three tanks, spread across every lane. When the clock has run out, you are free to secure victory.