Injustice: Gods Among Us
If you're a fan of DC Comics or the Batman and Superman type stuff, this is a must download. This is a completely free fighter game where you'll be able to battle with all of your favorite superheroes. Including the latest from the movie Suicide Squad. This game is a port of the Xbox and PS4 version, and it isn't exactly the same, so keep that in mind.
Either way it's still extremely fun, worth downloading, and will be something many can play for hours. Oh, and Injustice 2 is coming later this year. Might as well play this one while we wait, right?