I also agree that this review (and especially the score) seems a bit harsh, and I'll explain why I feel that way. Keep in mind, so far I've only played for a few hours on a throwaway account, and that the only other Lego games I've played were Lego Star Wars: The Video Game and Lego Star Wars II: The Original Trilogy on the GameCube.
First (and foremost), the Lego games are aimed at children. They are supposed to be games that you don't mind your kids playing, and that they can actually play. For that reason, and another I'll detail later, the combat is deliberately kept simple. Is it a button-masher? You bet it is. And it was made that way on purpose. Combat in games doesn't always need to be complex, involving endless combinations of button presses. And still, Lego Batman 2 offers more than just "mash the "A" button. If you *want* to, you can mix it up a bit by doing a jump attack or by throwing a Batarang (or using whatever special moves you get from the unlockable characters or variant suits. Any more complexity than that is unnecessary in this game, and making it so that you *have to* memorize combos in order to defeat enemies would only serve to turn off the demographic this game is primarily aimed at.
Second: While I like mini-maps as much as the next gamer, and I agree that in some games they are necessary, in this game they are *not*. When you go into a scripted story level (at least in the 4 that I've completed), gameplay is linear. Go from point A to point b, to point C, etc. You *can't* get lost, because there is only *one* way to go. When you're in Gotham City, follow the translucent blue studs to get to the next story location. If you're engaged in freeform play (as I was, after I unlocked the Batcomputer remote terminals), just press "Start" and select "View Map." And, really, after playing for a while, you should be able to remember which roads go to which locations. Also, when you're free-playing in Gotham City, a compass at the top of the screen shows icons for items/characters that may be of interest to you.. A mini-map in either of these modes would just be one more thing to clutter the HUD and drag your eyes away from what's going on on the screen.
And thirdly (and finally, since this reply is getting way longer than I had originally intended): Lego Batman 2 is *not* an action game (or a fighting game). It is a puzzle/adventure game, with action game trappings; just like the Joker is not an *actual clown, but a wacky homicidal lunatic *dressed* like a clown. As such, combat is mostly incidental to the gameplay. The purpose of the game is to solve puzzles, collect items, and unlock "treasures" (in this case, other playable characters). The combat is there (mostly) to mix things up a bit, and to add a bit of flavor to just pushing buttons, climbing walls, and picking things up. Think of it as the original Tomb Raider, but aimed at a younger audience.
Well, that and also because a superhero game without *some* kind of combat would just be stupid.
Sure, the gameplay doesn't change much in the Lego games, but it doesn't *need* to. Unlike the Call of Duty series, the *stories* are different enough to keep things interesting. Add that to the fact that different Lego games have character with different abilities, and plenty of different puzzles, and the series isn't really in danger of growing stale. Tt Games isn't just throwing a new coat of paint on a tired franchise and incrementing the number at the end of the title. As I noted at the top of this post, I've played Lego Star Wars I and II. I found the first one to be meh, and the second to be a bit better. On the other hand, I'm really enjoying Lego Batman 2 -- because sometimes I need to take a break from games that have simplistic stories and complicated gameplay, and play a game that has a more complex story and simple gameplay.
tl;dr: Lego Batman 2 is a fun play, and it's made for kids (even though grown-ups like me can enjoy it, too).