If you have ever played Allied General on the PlayStation, this game is almost a carbon copy in the way the game plays. The big difference, Allied General ran flawlessly, while Order Of Battle: World War has numerous flaws.
There are issues with the maps, for no apparent reason units cannot move through some hexes, and in the worse case they completely disappear. Now the lost unit is dead, and and has to be revived. No apparent battle, no enemy close by, bloop unit gone. If you attempt to enter the same hex with another unit, the same thing happens. So it has a serous map problem.
Path finding is horrendous, the map shows the distance you can travel, but its inaccurate. Often units will not arrive at the destination for various reasons, not apparent to the player. If an enemy unit is just off the path, I can understand a sudden halt to engage, but some units can only engage one type of target, such as some AA units cannot attack ground units. The path finding is a single click, so if the game decides to take a bad path into the jaws of the enemy, guess what your screwed by the AI.
Serious lock up issue with end of the AI's turn, basically its your turn, but you cannot proceed with any actions. Sometimes you can load the AI's last turn and it will work, but often I have had to restart the scenario.
The enemy has full game screen radar, and you don't. I have seen planes fly clear across the map and attack a unit, that for all intensive purposes should not be seen. Obviously the player cannot do that, since most units over a certain distance are hidden in the fog of war, and its only pure luck if you fly right to a target that is hidden. Since the player only gets one click to move, the AI should not path find while in transit, it obvious that that happens because they dodge other units to get there. The player only gets a straight line flight path for planes, and the AI's flight can dodge.

The free part of the game (boot camp) works quite well. But in the pay to play, it seems the larger maps have the most problems. I have assumed that some of the issues could be a memory leak issue causing unexpected lock-ups.

Overall, if i'm not cussing at the game, it is fun to play.