Anyone would be wary of a series that's had four games in six years; that's nigh-on Call of Duty levels. The only thing worse than seeing a favorite series dead in the water is seeing a favorite series milked to death. It is shocking that a game inspired by 1980s PC dungeon crawlers, a game where you draw your own maps, received enough attention to warrant three sequels. It is considerably more shocking that every one of them has been released in America. Anyone would be wary, but... they've certainly been pulling it off so far.

Etrian Odyssey IV has everything you'd expect from the series. It has the Atlus-style character designs: scruffy ruffians, and genki girls, and drowsy mages. It has a stunning Yuzo Koshiro soundtrack which dips from hard rock guitars and jazzy trumpets in the battle themes to gently strummed, almost pensive shamisens during dungeon exploration. It has player-drawn maps, the hallmark of the series, recalling fond nights of Wizardry and graph paper, but with the 21st century facilitation of a touch screen, and a stylus, and lots of fun little icons for denoting treasure and health-restoring oases. It is as intimidating as ever to enter a new floor and be faced with an enormous blank canvas. It is as satisfying as ever to pencil the lines of the dungeon walls, to dab in blue where there is water, and to place "pass through" arrows whenever a hidden crevice is found.

There's a handful of new classes and a handful of returning ones. Some bear adorably cumbersome names like 'Landsknecht.' Unlike their medieval German mercenary namesakes, Etrian Odyssey's Landsknechts tend to be green-haired anime girls with over-sized swords and a lot of pluck. Landsknecht train in skills that let them attack first at the cost of defense. Or maybe they don't, maybe they train in elemental strikes that follow every ally's attack with a burst of flame or lightning or cold. Or maybe they don't do that either, maybe they just juice their attack strength and sink the rest of their skill points into abilities that halve incoming damage to adjacent party members.

Most characters have this breadth of options and there's enough classes that you won't get to use them all. At least, not all at once, though you can swap party members in and out on a whim. A Medic can spec into skills that automatically heal the party after every battle. A Dancer bashes enemies from the front line, shoots enemies from the back line, and heals with the seductive power of their dance no matter where they're standing.

Series staples like 'chasers' (conditional automatic follow-up attacks) and 'binds' (debuffs that restrict body parts and prevent special attacks) return, sometimes in combination. A Sniper can bind an enemy boar's legs to prevent it from using its party-killing Rampage ability and then follow that binding shot with an auto-attack -- or three, if paired with the area of effect bind skills of an Arcanist.

And should the player start to feel too big for his britches, there are still FOEs to keep them in check. Field-On-Enemy in the Japanese version, some nonsense Latin phrase in the English, FOEs are free-roaming minibosses who act like roguelike monsters as opposed to the random-battle riffraff that poof into existence jRPG-style. FOEs have set movement patterns, different levels of aggression, and are usually significantly stronger than even their dungeon's end-boss. Some move one space for each step the player takes, some move two. Some ignore the player, some chase the party until it's out of their territory. This is the first game in the series to use 3D models for the enemies instead of static drawings, so its FOEs actually look like giant stags, or mountain-sized kangaroos, or blood-crazed red bears instead of nondescript floating yellow balls.

They all act differently and they all have their ways of being tricked. Bears pursue on sight and can be cajoled into crashing through wooden barricades, opening blocked-off paths for further exploration. Blind moths sit passively in out of the way spots, but make a beeline for the party once they hear the sounds of a battle. Diagonally-hopping frogs inhabit a water-filled dungeon where a careless player might become surrounded on three sides by lakes, with no escape except by forced amphibian encounter. Etrian Odyssey IV's first FOE: a giant, afro-ed baboon, is happy to ignore the player as it trundles about in a circular pattern. It could be easily avoided, but for the quest objective that lies in its patrol path.

FOEs display a dearth of honor. They move even when the player is in combat and they intrude upon a battles already in progress with no ceremony but a change to the battle theme. This leads to the game's most exciting scenarios, the times when a random battle coincides with FOE proximity, where every turn wasted fighting regular-sized boars and lynx and ethereal spell casters -- many of which are dangerous in groups of two or three, if not one on one -- gets the FOE one step closer to the party. Many a victory screen fades to show the party face to face with a giant moth: inert, now that the battle's finished, a morbid reminder that even one extra turn in any ho-hum fight could spell certain doom.

Frequently, you won't complete the battle in time. Frequently it is certain doom. Etrian Odyssey, as a series, is renowned for its difficulty, though IV introduces an easy mode that softens the enemy encounters a bit and sends a wiped party back to town instead of to a Game Over screen. It would be nice to have the latter without the former, so the challenge could remain without the gripping terror of losing an hour of progress.

But, well, that's kind of the point. Some of the best moments are those where survival hinges on a thread and a prayer. Early on the party unlocks a 100% escape ability that uses a limit break meter called "Burst," which recharges slowly as you attack. Having three levels of Burst at all times so you can use Full Retreat is basically a necessity, but Burst can also be consumed for double melee strikes, area of effect fire walls, and crippling mists extend the length of debuffs and binds. Sometimes you've spent all your Burst on killing a rare breed, golden monsters worth scads of experience, experience you may never spend if you get squished by an FOE on the way out.

Sometimes unexpected battles turn into stalling tactics. The front line defends while the back squeezes out futile attacks in the hopes of charging the limit gauge high enough to escape. These moments might not feel as fraught if the other side of a total party kill was a rest at the inn instead of the title screen. So it isn't quite as satisfying when a skin-of-the-teeth battle is completed on casual mode, but it will probably result in fewer thrown DSes.

Etrian Odyssey III's sailing mini-game has been replaced by an airship and a world map. Initially this comes off as disappointing, as the move-limited sailing of EO III played out like a puzzle game and was a nice break from the dungeon grind. The airship at first feels too similar to the dungeon crawls, with its giant too-high-level monsters roaming the plains and mountains just as they do the dungeon. However, with time the world map become quite large, with its own side-quests and its own perils, and the airship becomes stronger, able to ascend and descend to different planes, able to catapult food across the map to tempt monsters away from their treasure guarding. There are flora and fauna to be collected and cooked for temporary bonuses or to be used as a combat-free cash influx on the not-so-rare occasions when a battered party can't afford resurrections and a night at the inn. There are hidden coves representing themed micro-dungeons. Some are filled with helpless frolicking fawns (and their angry parents). Some are attached to side-quests that grant exciting new abilities or chunks of always-needed cash.

For older players who remember games like Wizardry and Bard's Tale, Etrian Odyssey rekindles the ceaseless fear and ceaseless wonder of the unknown, where a budding fruit found in a nondescript tile in a corner of the map could heal the party to full health or near-kill them outright. For the younger crowd there's enough anime artwork and user-friendly mechanics, like low-cost skill respecs, to bridge the gap. Either way, what's most interesting is how often the player feels completely in control. For a game without any tutorial to speak of and with skill trees that read like corporate flowcharts, Etrian Odyssey is surprisingly proficient at teaching without resorting to hammy screens of instructional text. Even a few hours in, an Etrian Odyssey player feels like an old pro: using a low initiative Medic to cure big damage from a hit that's yet to happen, ceaselessly binding arms and legs to neuter a FOE high above the party's level.

But, no matter how "in control" the player feels, Etrian Odyssey keeps finding ways to surprise. It is kind, when it warns "the boss is in the next room" or when it hints at the strategy to catch a huge monster from behind. It is exceptionally cruel, when it capitalizes on mistakes, hammering enemy attack after enemy attack when the player is at their most vulnerable. It is exciting, when it drip feeds meta-upgrades such as subclasses and new Burst abilities.

For a game so seemingly pitiless, for a game that requires such rigorous involvement, Etrian Odyssey is surprisingly reserved. There is never any hint of hand-holding. When a secret passage is found, or when a puzzle is unlocked and a chest acquired, or when a dungeon boss is toppled, the game steps out of the way and lets the player enjoy their victory. It doesn't need a dialogue box reminder that the day was won; the sublime satisfaction of a hand-drawn map in the player's hands is evidence enough. To be so restrained, and yet so magnanimous, is what makes Etrian Odyssey special. What's truly astonishing is that it's been doing it for four games, each one better than the last.