LEGO Batman wasn't my first lego game, but despite the rich story and setting it could have used it felt very formulaic and just flat. Though it was a lego game, so it's still at least tolerable, I had luck and didn't have to endure the bugs people reported around me.
Good things about the game: it's lego . Fun, beat everything up, get lego studs, unlock stuff, replay level with unlocked stuffs to unlock EEEEEVERYTHIIING.

The bad part is that they made a Batman game where you spend literally half of the game playing Batman and Robin, who are the most boring characters in the campaigns, has the least smooth gameplay and barely add any personality to the game, other than the well-known face/mask. Why?
The story is 3 chapters, each of the chapters having a gang of supervillains escape and setting up an intricate plan, organized by a super-supervillain. With B&R you go after them in 5 missions and foil their plan. Then in the another 5, you play as the supervillains and play almost the same levels, but your evil plan succeeds. This leads to an important consequence: you play half of the game (15 levels) with B&R, and the much more interesting, fun and viable villains get like 2? 3? levels on average.

For one, the game is so formulaic that there's a vehicle level (twice, as it's from both sides) in every chapter, those levels have no identity, you don't even see your character. Second, Batman and Robin doesn't have superpowers. They have a shitty "wind-up" batarang attack, while supervillains have instantenously firing guns / superpowers. You need to build, then use power-up platforms to change your suit so you can hover, have magnet boots, glass-shattering sonic gun, etc. But after you use them, or after the level ends, your suit just resets to the simple, boring one. Only so you can later unlock and use it again, then cast aside again.

To emphasize how flat they are, the very first level in the villain campaign you start with Clayface you has double jump AND superpower so can throw away blockades AND does double damage to enemies. It was a joy to play with him, only to then go back to boring old bats in the next chapter.
And Clayface isn't the sole enemy with double damage. Poison Ivy, Dr Freeze, Cat Woman and technically the Joker all have either double damage, attacking a lot faster than the heroes, or in case of the Joker having two guns = double the damage. And you need this damage because the game SWARMS you with copy-pasted henchmen, lackeys, thugs and goons. Most of them have guns, and it's really not that fun to play against guns with mostly melee characters. At points I was fighting 10-10+ enemies who barely add anything to the game. And playing with the double damaging villains is what makes the tempo really enjoyable, imo.

Overall it's one of the most meh lego games, but it's still kinda fine if you get to avoid the bugs. I think the main issue is that it was the first game, maybe was underfunded, but definitely did not try to be creative with the story, at least Batman's side is extremely repetitive other than the bossfights. You don't get to play Bruce Wayne, Gordon, Batgirl, Nightwing, where difference of their personality and role / job would have made a real variety - but they are available for characters to buy. Maybe I missed something, maybe they were planning ahead? I don't know.