I just recently purchased Injustice 2 earlier this week. I am really not into fighting games nor am I a DC fan but I very much LOVE playing Injustice 2! The main story is great and allows you to play some of the other characters and try out their move sets. The game also has a loot system giving you a wide variety of costume add-on items and powers for your character while playing Story and Multiverse mode, both are offline and solo (which is fine with me because I know I'd get my ass handed to me playing against an actual person online). In addition, Multiverse mode also refreshes very frequently with new worlds and battle challenges to play (such as fighting with no powers, slow-mo, etc) this adds huge replay value and I can't get enough of it!
I think Injustice 2 is well worth it if you're into games with lots of content, replay value and even if you're aren't a fighting-game gamer you'll be addicted to this! Highly recommended, check it out!