This is one of the FUNNEST games I've played in a very long time, I highly recommend purchasing this, it is easily worth $60 but the developers are friggin awesome and sell it at a very low price.
This game is like battlefield, but in top-down view. Running with Rifles in my opinion can easily rival battlefield, if not better. Single-player is great, the campaigns are pretty difficult. I'm still on the first campaign and it's been 5 hours lol. The battles are very rewarding, that feeling after an hour struggle to capture a point is very satisfying.
One thing that might be awkward at first, but maybe not for some, is the aiming system. When moving your cursor to aim, it kind of "pulls" on your screen. This system is pretty neat because it lets you see farther and kill enemies that are further away and different weapons have different pull ranges. I'm still trying to adjust to this, but it's really not too bad.
The movement keys are pretty simple, WASD to move and mouse to shoot, which I like.
At first this game may seem simple, which it is, you can just hop in and start killing enemies, but this game has WAYY much more depth than that. There is a huge selection of weaponry, you can create defenses such as building crates and putting a turret behind them, calling in airstrikes or supply drops, driving convoy trucks to move your soldiers across the battle zone, defending a captured area, and much more.
I know the "early access" tag will give you doubts, I know that feeling just look at some of my "early access" games. But this Running with rifles is pretty much completed and can be enjoyed to the fullest experience. I've read on their forums that this game is due to be released in about two months (assuming no delays), so they're pretty much just polishing this game from this point. You pretty much have the full game now, but just be aware it can be subjected to change and other stuff.
I can seriously go on for a while about how great this game is, but I'm going to end it here. If you have a slight interest in buying this game, buy it, you will not be disappointed. Any fan of shooters will definitely appreciate this game, hell you might even be addicted to it just like I am now :D