The problem with many fitness games is that they're lacking when it comes to fun. Which is one of the main reasons to gamify physical activities: If players feel that they're playing a game rather than doing a shift on the old treadmill, they're more likely to keep at it.

The best fitness games push players to beat high scores or advance a narrative. With "Ring Fit Adventure," Nintendo melds exercises into a role-playing action game (RPG).

Most fitness games are 80% exercise and 20% gameplay; "Ring Fit" flips that ratio. Players take on the role of a newcomer who stumbles upon an ancient artifact and is fooled into releasing Dragaux, a dragon obsessed with weightlifting who threatens this fantasy realm.

Players are tasked with stopping Dragaux. It's difficult but manageable thanks to Ring, a talking artifact that guides players through a journey spanning more than 20 worlds and 100 levels.

The fitness aspect of "Ring Fit Adventure" comes in the game's peripherals. The first is a thigh strap with a Joy-Con holster. It lets the Switch detect leg movement, such as running in place. The other piece of furniture is a ring that looks like the game's sentient sidekick. Players attach the second Joy-Con to the device and that move turns into what Nintendo calls a Ring-Con. Players squeeze it, pull at the sides and move it around their bodies as part of the exercises.

What's fascinating about "Ring Fit Adventure" is that it's organized more like a video game such as "Super Mario Bros. 3" or "Final Fantasy." Players tackle a level and run in place to make their avatars sprint across the screen. They can squeeze the Ring-Con to blow air that knocks down doors or tussles objects in the environment. By pulling at sides, they can suck up objects in the immediate vicinity. By turning their hips, players can aim the ring in different directions, including at the ground, which lets players hurdle obstacles.

Thankfully, "Ring Fit" is more than just running an obstacle course. That would grow boring fast. Shuffled into each stage are monsters that players must battle. They perform attacks by running through exercise routines that work out a section of the body. Players may have to hold the ring above their heads and squeeze to burn calories in their deltoids. Other tasks asks players to sit down and perform leg lifts. Others have them doing yoga poses.

In true RPG fashion, players must battle enemies and complete tasks to earn the points needed to level up, which strengthens their characters' attack and defense stats. Meanwhile, the coins they earn can be used for gear that offers stat boosts, or smoothies that heal players and provide a short-term bonus in fights.

The game is surprisingly deep. It does a good job at masking rote workouts with rewarding RPG elements — and the exercises actually work. After playing through a world, players' muscles will be sore the next day. They can even check their heart rate via the IR camera on the Ring-Con, though it's not as accurate as an Apple watch.

With a nearly flawless balance of gameplay and exercise, "Ring Fit Adventure" can nudge players toward an active lifestyle without making it a chore.