In battle, "Costume Quest's" heroes transform into mighty warriors, including a knight, a ninja and the Statue of Liberty.

With “Costume Quest,” Double Fine Productions’ Tasha Harris achieves what she set out to do: make a video game steeped in Halloween nostalgia.

From the very first scene, when siblings Wren and Reynold are sent out into their new suburban neighborhood to make friends with other children, minus any adult supervision, it’s apparent “Costume Quest” is a paean to the way Halloween used to be, before mom or dad had to check each piece of candy for nails and razor blades.

As I spelled out in a preview earlier this week, “Costume Quest” is about a boy or girl (you choose) on a quest to find her missing fraternal twin, who was dressed as a piece of candy corn and kidnapped by candy-loving monsters. Just as you would with classic, late-’80s/early ’90s role-playing games, you’ll hook up with a couple of companions, battle clusters of bad guys, earn experience point and collect new equipment.

What sets “Costume Quest” apart from all those role-playing games of yore is that is new equipment comes in the form of Halloween costumes, which magically transform their wearer when it’s time to do battle. The Statue of Liberty, for example, shoots flame out of her torch and sings a patriotic anthem that heals the party, while a ninja can temporarily make one of her teammates invisible to attackers.

As is the case with all RPGs, fighting is but a small part of “Costume Quest.” The best part of playing it involves simply wandering around the three levels, checking out the scenery and talking to everyone. (It’s worth noting that the game isn’t voice-acted; you’ll actually be reading all the dialogue.)

There’s a certain echo of the “Peanuts” holiday specials in the way the characters communicate. Just as Charlie Brown and pals did, the children of “Costume Quest” have a knack for for delivering jarringly mature dialogue that’s as amusing as it is insightful. The echo of Schulz’s timeless holiday specials imparts an infectious warmth. It’s impossible to play through “Costume Quest” without smiling at its whimsical artistic direction or laughing at an unexpected line of dialogue.

Winning battles will net you experience points for leveling up and candy, used to purchase certain abilities.

But where the dialogue and art style are flawless, the simplistic battles can become repetitious. Every fight can be summarized thusly: Press a button to attack with a character. After the button-press, follow the on-screen button or joystick prompt to dish out more damage. When the enemy attacks, press a button to dodge or mitigate the damage.

Every three turns, each of your characters will have the opportunity to use a special, costume-based power. The Statue of Liberty, for example, sings a patriotic anthem, represented by a hilarious graphic with a screaming eagle and Abraham Lincoln. I won’t spoil it, but a French fry costume you acquire relatively late in the game is “Costume Quest’s” most inspired get-up.

There’s a modicum of strategic potential in trying to optimize the use of your different costume-based abilities, or in managing your party to create the right mix of special abilities for a particularly tough fight. It’s too bad, then, that most of “Costume Quest’s” combat is so easy that players don’t really get to explore this potential until the game’s final two boss battles. Once you’re tantalized by an opportunity for more nuanced gameplay or a variety of strategies, the game’s over.

At times it feels like “Costume Quest” is conflicted about whether it’s aimed squarely at kids or nostalgic, literary minded adults. The dialogue, some of it no doubt written by Double Fine’s studio head Tim Schafer, occupies the same linguistic terrain as the stuff you might hear on “The Simpsons” in its heyday. Plenty of laughs will trickle down to even the youngest players, but their parents or older siblings will better appreciate some of the more off-kilter dialogue, such as a monster who tells the kids, “You look just like my parents, from whom I’m bitterly estranged!”

As tough as it must be to write humor that appeals both to 6-year-olds and 60-year-olds, designing a kids game that appeals both to kindergarten-age gaming newbies and lifelong players well into their middle ages is a tall order. Double Fine’s solution seems to have been to try to make the game playable by as large an age range of gamers as possible, and the result is a game that doesn’t dazzle quite as much as it should.

That said, the combat doesn’t drag down the game all that much. Harris and her cohorts at Double Fine keep the laughs and good feelings coming with such regularity that having to briskly battle through a few dozen skirmishes is a small price to pay.

“Costume Quest,” rated E10+, is available as a $15 download for the Xbox 360 or PlayStation 3.