Darkest of Days is not even worth playing.
Everything begins with a good idea. Game's protagonist, Alexander Morris is going to be sent to the different points of the history in order to save some good guys –who could have turned the world into a better place- and stop the happening of some disasters that actually has happened. For example he will engage in the battle of Antietam as the bloodiest battle of the USA's Civil Wars or battle of Tannenberg in Russia that has had more than 1400 victims. However time traveling has become a common idea in gaming, but being in the different battles inspires a wide variety to the Darkest of Days' gameplay.
Actions and battles easily have been ruined because of inappropriate using of the elements of the gameplay. Maps are too large just like the strategy games' maps, not an action FPS! Of course having large maps isn't a lake for the gameplay, but not using them most of the time and staying untouched of these maps –even when the entire game is done- is a big problem. For example when you are trying to cross a field from a side way, you may be facing a "block" sign when you can see other side's environments. Unlike a game like Farcry 2 in which you were able to use the vehicles to pass the ways, in Darkest of Days there are no vehicles and you have to walk even for the long distances. The game is supposed to be open-world but when you can't go through most of areas, you can't name it an open-world game. However Morris uses a GPS to acquire targets and different places, but I'm sure if he hadn't that equipment nothing would change.
Variety of weapons in game is acceptable and all weapons, from the old ones to moderns will be used. Using old weapon is something catastrophe because not only they don't have much power, but also reloading them will take a long time, in purpose of making them feel more real! This easily can be a cause of you getting killed among the battles and because of that, the beginning battles in which you don't have modern weapons in hand and have to use the old ones will be so challenging. Shooting section's problems will be completed with the weak aiming and awful AI of the enemies. Sometimes none of your shots hit the enemies even from a short distance and sometimes their shots will hit you even from a 1KM distance, without knowing who is shooting you and where is he! If you want to test enemies' AI, just walk around them in a cycle and watch their reactions! So you can't expect any kind of organized plans or logical covering from them.
You can forgive the mistake of making enemies all the same with just one design for their faces, but when it comes to the similarity between enemies and teammates, you can't get along with it. Sometimes the similarities between your teammates and enemies is so much that will make you confused about who's on your side and who isn't and it leaves you no choice except shooting anyone in your sight. Fortunately there is no friend shot in game so you will not kill your teammates in this kind of situations otherwise completing levels would be impossible.
There are a lot of problems in game's graphics and sounds too. The game is full of bugs like characters' stocking in areas. Environments' details isn't good enough to attract you and its art design isn't artistic at all! Characters' animations is abstract so you feel you are dealing with robots instead of human soldiers! They seem totally without any feelings while talking and it's better not to talk about Lip Sync when there is no such thing in game! Maybe the best part of the game's graphics is weapons' design that has been better than other parts.
At the end I must say that Darkest of Days is not even worth playing. Fortunately because of not having any online mode, there will remain no reason to play this worthless game.