I remember when was the last time I got excited about Metroidvania. It was "Axiom Verge," a game more inspired by the original "Metroid" than "Symphony of the Night." Like "Metroid," "Axiom" was set in a dark and mysterious world that felt particularly open to investigation, thanks in part to a device called the "Axiom Disruptor. This is a gun that can "hack" parts of the game world, turning enemies into friends or removing glitched obstacles. Never mind that this is just another key in disguise in a genre that is rife with overt and covert locks.

I mention the "disruptor" because, despite being an iconic element of the original game, it is absent from this audacious sequel. It is emblematic of a game that has managed to retain its soul while changing almost every aspect of its predecessor.

Once again, you play as a human who has been transported to another world. It is a land full of killer drones, where two civilizations once fought a devastating war. It is a philosophical story that touches on artificial intelligence and multiverse theory, but it is told so lightly that it may be difficult to follow. Heavier consideration is left to the collectible material, and that material fills in many of the gaps.

Storytelling is so restrained that you are never told who you are or even why you came to Antarctica. I thought so until I discovered the intro sequence that plays if you don't press anything on the main menu. By the way, you are Indra Chaudhary, a billionaire CEO who has been summoned to Antarctica, and by extension, to an alien planet, to search for his daughter's whereabouts.

While "Axiom Verge" was largely subterranean and filled with jet-black backgrounds and pulsating alien flora and fauna, the sequel is set in a more orthodox overworld. The backgrounds suggest a vastness beyond the 2D play area, and the underground is more detailed. If the first game evoked the subterranean terror of Metroid, Axiom Verge 2 is more symphonic, offering a gorgeous, detailed environment that's worth hacking and slashing through.

Notice that I did not say "shoot." Many guns from the original are completely eliminated, leaving only melee weapons and Zelda-style boomerangs. Imagine Samus replacing her arm cannon with a nickel and a bit of wood, but thankfully melee combat is not a problem. It's a little less satisfying than the bullet bustle of the previous film, but it's good enough.

There is just as much combat here, with one important exception. There is no boss battle in "Axiom Verge 2. Oh, there is a formal final battle and an optional scrap against a unique enemy. But there's no locked-off boss arena, and aside from two encounters with villains, you're not grinding down a giant health bar to advance; Axiom Verge 2 doesn't want to interrupt the flow of exploration. Therefore, as someone who fears the bosses in Hollow Knight, I am all for this change.

It seems odd to say that combat has been de-emphasized in a game full of diverse enemies, but that's only because the exploration aspect has been so heavily reworked. The newly fleshed out world encompasses several different biomes and is connected in a more organic way than its boxy predecessor. However, its distinguishing feature is actually borrowed from "The Legend of Zelda," where another world exists parallel to this one.

You have probably seen this feature in other games such as Metroidvania. Not so here. The Breach is a separate map placed above or below the primary map, but the layout is almost entirely different, and the visual style is completely different, with the ultra-low resolution and color palette not seen since 70's SF.

In the more cramped "Breach," you take control of an adorable drone sidekick and listen to cover versions of synth progressive music while you whack enemies and avoid traps. It's an intoxicating place, and contrasts favorably with the grounded nature of the overworld.

"Breach" opens up the game in a big way, especially when you have more freedom to move between worlds, and Axiom Verge 2 is a game in which the unexplored map sections are actually clever navigation puzzles, even more so than in the previous game. Which ability is needed here, and which part of the map should I approach this obstacle from? Can I get around this obstacle or should I come back later?" Discovering the solution is usually more satisfying than finding the knick-knacks that await as a reward.

There are situations where the game could be more accommodating. There were a few times while struggling with the world's most unwieldy grappling hook that I finally, after dozens of failed attempts, succeeded in being merciful. Unless there was an ability I missed (I was able to explore most of the map and finish the game without it), these half-dozen jumps are truly unforgiving, requiring almost pixel-perfect precision, setting them apart from the rest of the game.

Also, as was the case in the first game, I found myself completely stuck at one point. Almost from the start, you can sprawl out in multiple directions and bang your head against multiple brick walls. Guidance has improved a bit in this sequel, however. A new compass appears on screen to provide (reassuringly vague) assistance, but it's also easier to orient yourself in the more organic world.

Whether it's a better game or not is hard to say, but it's certainly a vastly different and more ambitious one, and Axiom Verge 2 builds on its predecessor as well as Symphony of the Night and A Link to the Past to create a beautifully intricate exploration space. Axiom Verge 2 is a beautifully intricate exploration space that builds on not only its predecessor, but also Symphony of the Night and A Link to the Past.