Originally published on April 28, 2015. Video games are more than just a good time. America’s military has long been a pioneer at using...

Originally published on April 28, 2015.

Video games are more than just a good time. America’s military has long been a pioneer at using them to teach, educate and recruit.

Marines once played a modified version of the popular shooter Doom II in the classroom. America’s Army and its sequels continue to be an important recruiting tool for the Army.

But games can also teach history and strategy. In 2014, James Lacey — a professor at the Marine Corps War College — designed part of his war, policy and strategy course around a computer game called Darkest Hour.

During the course, Lacey set real soldiers against each other during a simulated version of World War II. The result was extremely ahistorical. Japan invaded India and inflicted massive losses on the Allies, the invasion of Italy nearly resulted in disaster … and D-Day came early.

Darkest Hour is part of the Hearts of Iron series of grand strategy games developed by Paradox Interactive. The games in their different iterations take players through Europe’s history from the 1930s into the 1950s.

Hearts of Iron games are notoriously complicated, difficult and long. Players could spend hours just planning their moves. The player must deal with politics, diplomacy, weapon production, troop movement and dozens of other moving pieces to advance in the game.

They’re tough to play, and often feel like moving numbers on a spreadsheet. And that’s the point.

According to Lacey’s after-action report on the exercise, he wanted a game that would challenge his students to consider all the strategic implication of World War II. To that end, he took his 30 students and divided them up into three teams — the United States, United Kingdom and the Soviet Union.

The three teams would play just one year of the war — from November 1942 to October 1943 — and they would face outside experts brought in by Lacey to play Germany and Japan.

The first thing the students did was reorganize. The Soviet Union had to fend for itself, but the U.K. and U.S. leaders consolidated — creating joint chiefs of staff to handle the war in Europe and another for the Pacific. Members from each country comprised these staffs. They looked at the entire campaign map, decided on strategy and then delegated to individual theater commanders to carry out orders.

The Allied forces in Europe moved fast and beat the Hell out of Germany and Italy. The first target was North Africa, and the Allies moved through the region with speed, using a series of amphibious assaults to push Germany’s army out of Africa. Next, the players knocked Italy out of the war.

The students dumped resources into the production of war machines. They were ready for D-Day far sooner than happened in reality. The students set the invasion for Sept. 21, 1943.

In preparation, the students’ forces feinted toward Rotterdam with a naval assault, tricking Germany into moving divisions there. The main assault occurred in Bordeaux. It was a success, but the game ended before the Allies could push farther into Europe.

The Pacific campaign didn’t go as well. The students focused on destroying Japan’s main fleet and ended up chasing it across the waters while Japan invaded India. The Japanese offensive moved through the sub-continent and captured Calcutta, Dhaka and Bhutan before the Allied forces stopped it.

But the Japanese offensive in India left the Pacific wide open. Allied forces moved through the region, conquered islands and cut off Japan from its oil supplies. All the while, the students chased the Japanese main fleet. They finally confronted the sea power in August near the Gulf of Tonkin.

Japan crushed the Allied fleet.

Japan’s naval forces destroyed three carriers and 12 battleships. The remains of the Allied navy escaped east, pursued by Japanese forces.

The Eastern Front also went poorly. The Soviet students aimed to defend Moscow and Leningrad before defeating the German 6th Army. The players did protect Russia, but the clever German player took Leningrad and Murmansk before pushing into important oil fields in Baku.

The distressed Soviet leadership pulled forces from the east to push back the rampaging Nazi forces. It was a mistake. Japan looked at weakened Russia as an opportunity. It attacked and took control of Vladivostok. During the 11 months of game time, the Soviets lost more than five million soldiers to either death, capture and desertion. The Nazis only lost 1.2 million on all fronts.

Lacey praised Darkest Hour and the exercise in his after-action report. “The students emerged with a superb grasp of the major strategic issues driving WWII grand strategy,” he wrote.

But he noted that the complicated and tricky game sometimes hampered the students’ ability to play and learn. “There were many times in the course of the exercise where student lack of proficiency in Darkest Hour, and limited understanding of the nuances of the game, served as a handicap to implementing strategy,” Lacey explained.

It turns out that any of World War II’s major amphibious assaults such as Operation Overlord — the famous D-Day — required students to have mastered the game’s mechanics.

This played out during the simulation’s version of the Battle of Anzio — an Allied landing in Italy in 1944. In real life, the Battle of Anzio started as Operation Shingle — part of the Allied plan to break into Italy, flank the German army and set up an Allied assault on Rome.

Historically, five cruisers, 24 destroyers and more than 40,000 troops divided into three different battlegroups assaulted positions along Germany’s Winter Line in Italy.

After a month of fighting, the Allied forces captured Rome but failed to defeat part of Germany’s 10th Army. It rejoined with German forces in the north and made trouble for the Allies later in the war.

It didn’t go anywhere near as well in the Marines’ Darkest Hour campaign. Amphibious assaults are incredibly complicated affairs that need a high level of planning and coordination. Allied commanders planned Operation Shingle for months.

Seven students spent 30 minutes planning the digital equivalent. The Axis powers devastated the Allies at Anzio, eliminating 24 divisions of video game soldiers. Tens of thousands of digital soldiers slaughtered because the commanders didn’t understand the game.

To be fair, Lacey reverted to an earlier save game, and the Allies tried again successfully. But the after-action review noted that the Battle of Anzio highlighted a major flaw in using Darkest Hour to teach tactics — it’s way too complicated to pick up immediately.

“The time required to master Darkest Hour is significant given the game’s complexity,” Lacey explained. “This challenges how Darkest Hour is utilized to support education. Schools cannot afford to devote the time required to fully educate students on Darkest Hour game mechanics.”

But despite the challenges of the system, Darkest Hour taught young Marines about strategy, history and diplomacy. As video games mature, more and more classrooms will use them to teach students on a variety of topics.

And the military will continue to pioneer their use.