XCOM 2 is just $3 on Steam for a day—cheaper than the bus I took into work this morning, or 1/5th of a World of Warcraft subscription
XCOM 2 is such a good game that I feel strange doing my due diligence to explain it to the unfamiliar—but in case you've not heard of Firaxis' turn-based tactics masterpiece, let me lay the grid out for you.