Two of the biggest things I would note, which are commonly mentioned when the Beta came out are the tanks and the weaponry.

Simply put the tanks are too fast and have too little trouble with the terrain. The Various Mark's slowly increased in speed, but even then the Mark IV tank topped out at only about 5mph. A brisk walking speed. And they could have serious trouble crossing uneven terrain and debris.

While the vast majority of the infantry portrayed should be using bolt action rifles of various makes depending on nation, location, and date. Even late war, with the inclusion of trench guns at times, rifle grenades or bombs, and a handful of automatic weapons at the Platoon level, most everyone was still using bolt action rifles.