If you like FPS & RPG style game play then Fallen Earth is well worth the time. Innovative, immersive and addictive.
The battle system is what it should be, by allowing you to aim and move around while still attacking the target the game gives you a sense that your control and reflexes (with a keyboard & mouse) are valuable.
The character build is highly customizable, by allowing modification over time you are never stuck with only one path instead you are given a choice to adjust your attributes and skills to suit your play style.
The crafting system is among the most deep and immersible mechanics of the game, it will allow you to create from the simplest items to the most high-tech (vehicles, weapons, armor, etc.) all using a real time element. for example, a cooking item such as grilled chicken will take you 3 to 4 minutes while a vehicle will take you weeks to build all the components and put them together. Another plus side to the realism is that your items can be left to build while you are on-line or off-line.
The story so far seems interesting but needs to be explored further to get a fair review. As for a the down side, i really don't have one, although this is a new game with plenty of bugs, the tech support is great and are working constantly toward clearing out the kinks.
Overall this game is well worth the late nights and tired mornings you may have.