not too shabby, really.
Well, I wasn't exactly dreaming of the opportunity, but it does make for a little more variety in what is otherwise a somewhat plodding beat-em-up. To call this an action RPG really pushes the definition of RPG, since there is no way to tailor your heroes or boost characteristics manually at all. The only hints of RPG come when your character 'levels up', which results in a slight autoboost of traits, and sometimes unlocks a new superpower. Otherwise, you have no say in determining the makeup of your heroes. Other reviews appear to liken this game to the X-men incarnation of the PSP, and while there seem to be some superficial similarities, JLH lacks the character-development depth found in the X-men, but this fact may not be noticed by some folks just itching to try out Wonder Woman's Golden Lariot. However, I'm not sure what right they have calling this an RPG, since that phrase seems entirely to mean that you play "as" a superhero instead of yourself. By that logic, Pacman and Pong are RPGs, since you play "as" a small yellow globe or a straight line.
So lets call this what it is: a theme-based beat-em-up, where the theme is superheros and their traditional enemies, and you take your character through largely linear maps of buildings, streets, rooftops, and so on, slaying everything in your path. Without the character development, this game gets a little dull after a while, although on-the-fly switching between an assortment of heroes results in a different 'feel' . Flash runs faster, hits faster, but is ultimately weaker; Batman is sluggish by comparison, but packs a huge punch, and can stun his enemies. Superman isn't indestructible, but does take more damage, and has the ability to fly. You get the idea: each character will still punch, kick, and use a special power, but in a slightly different way, resulting in a slightly different experience when you switch out.
There is a story, driven by text and nicely rendered stills; something about a meteor hitting, and all these robots attacking various locations. As you play, the mystery of who is controlling the robots unfolds. There is no on-the-fly saving, just an autosave before each new section of the story (with their collection of 3-5 maps) begins.
Strangely, the first ten minutes or so is actually the most difficult in the game, as you wade in with Flash, try to beat up the first few robots, and discover your characters aren't really *that* super at all; I had to re-start the first level several times before finishing without one or both of my heroes (you can select two to take into each map, and switch between them at will) dying in the process. Essentially it entails you running up, hitting a bad guy a few times, then running away and waiting for your hit points to regenerate (which they do automatically, or with powerups found by smashing boxes etc). Once you begin to unlock the super moves, however, the game gets much simpler, since they are quite powerful (one hit kills), and can often occur as ranged attacks (like Superman's heat vision), meaning you can stay out of harm's way and deal damage. Each map ends with a boss, who are not that difficult if you have levelled up sufficiently, and have a few special moves. So, the game becomes hit, special move, hit, wait to heal, kill the boss, get the next sequence of story, hit, special move, etc.etc.
Luckily, the sound and graphics are smooth, clean, and easy on the eyes (VERY similar to PSP's X-Men Legends), so this repetitive process doesn't really get on your nerves at all.
Also, you can go back and replay finished sections with different heroes, just to make sure everyone levels up evenly; finally, there are "subquests" in some levels, which end up being "find the four civilians in the map", or "destroy the four beacons". Nothing too serious, and does not side-track you from your main quest of finishing, since it all takes place in the same map.
In summary, it is a decent but slightly short theme-based fighting game, with good graphics and sound, an OK story that keeps you guessing whodunit, and mildly repetitive gameplay that is tempered by being able to select between a half-dozen different recongizable heroes. Being one of the cheaper DS games released recently, it is worth it, if only for a week.