Honest opinion.
If you can accept that this game is not an Arkham clone/sequel/spin-off then you might actually enjoy it.
It's a solid action RPG that has the addition of puzzles, stealth combat, crime scene investigation and co-op.
It features cool melee moves, unique abilities and skill trees for each character.
The story itself is pretty solid, slightly predictable but you are solving crimes throughout the game... It doesn't take batman to figure out where the story was going with key plot points and bad guy identities. However it still kept me interested to the end and to what comes next.
Endgame is currently a typical rpg style... A gear grind. So once you reach the current max level you will be stopping crimes and hunting down Gotham's most wanted for legendary schematics and crafting materials.
Thankfully the gear is pretty diverse and you will be using various combinations to cater to your own play style... So you have a reason to grind.
And with over 20 different legendaries per type (armor/melee weapon/ranged weapon) that's 60+ legendaries per character.
Co-Op is also pretty fun especially since you aren't tethered to each other and can be on opposite sides of Gotham clearing crime activities while still rewarding each other with items from event completions.
Why not five stars? Well the game needs more.
More enemy factions, more mission variety, more playable characters and more Villain/hero cameos... But this game has had an incredible start considering how many games are just disappointments lately.
All in all for a base game with very few bugs and only a handful of crashes it's been a great game.