You play as that tiny girl on the left.

Shoot-‘em-up-style games, which require players to blast everything that moves while avoiding enemy fire, have been around at least since “Space Invaders.” But the genre, while producing excellent titles such as “Ikaruga” and “Rez,” stopped being a hit maker long ago. Don’t tell that to fans of Japanese shoot-’em-up gods Cave, whose “Deathsmiles” is the studio’s first game to get a proper U.S. retail release.

“Deathsmiles” (rated T, $50) might be the year’s strangest retail game. It’s a two-dimensional affair that scrolls at a fixed speed and requires players to negotiate a “bullet hell” minefield with lightning-quick reflexes and memorization of attack patterns. But where classic titles in the genre featured spaceship protagonists, “Deathsmiles” stars “gothic lolitas,” essentially flying teenage girls in frilly dresses. (For the most part, it’s less pervy than it sounds.)

Why gothic lolitas? Dunno. One can only assume that it’s because the Japanese, who’ve always played more shoot-‘em-ups than us Americans, became jaded by playing spaceship game after spaceship game, and flying, school-aged girls with animal companions seemed like a great way to shake things up. Don’t question it. It’s delightfully odd and fantastically Japanese.

What could a giant tree use to attack a flying girl in a frilly dress? Why, giant smiling apples, of course.

But the strangeness goes far beyond the five heroines, each of whom plays slightly differently. The girls have been separated from their families, trapped in a world overrun by flying eyeballs, malicious, dancing couples and fire-breathing demons. At one point, you fight a giant cow that looks like it was designed using an entirely different game engine, then dropped into “Deathsmiles” in the video game equivalent of a bad PhotoShop job. And who’s responsible for all this evil? A man named Jitterbug.

It takes maybe an hour to finish, depending on whether you play optional, bonus levels that increase your score but are absurdly tough. Lest you grow weary of the repetition, the game ships with several different modes and difficulty levels, as well as online and offline co-op play. Online leaderboards and saved replays allow you to download videos of top players, both a useful learning tool and a tremendous way to feel inadequate.

If you haven’t played a shoot-’em-up in a while, you’ll need to get used to the concept of a hit box. Take a look at the girls in the screen shots, and you’ll notice they have a little red heart at their center. In “Deathsmiles,” that’s the only part of the girls that matters. Bullets pass right through their heads and legs without harming them. I’ve played through the game multiple times on every difficulty level and in every game type, and I’m still trying to get used to the concept.

Despite its punishing difficulty at more advanced levels, “Deathsmiles” is a great introduction (or, in my case, reintroduction) to an often-overlooked genre. It lets players continue an unlimited number of times, ensuring anyone can “beat” the game, but it resets the score each time you continue, keeping its leaderboards populated by only the best players. (And the only way to qualify for the online leaderboards is a special, “score attack” mode.)

In other words, “Deathsmiles” manages to be great fan service to shoot-’em-up diehards, and devotees of Cave’s games in particular. But the developers were also smart enough to keep things accessible for the rest of us. More casual players may balk at the idea of paying $50 for a game that can be finished in an hour, but publisher Aksys Games has tried to sweeten the pot by packaging the game in a limited edition featuring a soundtrack CD and faceplate. (As of right now, the “limited edition” is the only version available.)

If you’re a casual fan of old-school shoot-’em-ups with a little money to throw around and are looking for a change of pace, you could do a lot worse than “Deathsmiles.” This carnival of oddities has to be played to be believed.