Unlike in most video games of the time, the game's challenge comes mostly through impeding player progress by implementing physical obstacles, puzzle-solving or paths blocked by coin or treasure locks, or forcing Wario back to previously-visited areas. By finding hidden exits in some stages, the player can change the direction of the game's plot and uncover different endings, as well as find more treasure. In addition to the Really Final Chapter, five other endings can be unlocked by collecting all the treasures. An enemy-themed Simon Says minigame based on the Game & Watch game Flagman can be unlocked by collecting all the picture tiles. Wario does not have any life points and cannot die; some enemy attacks simply knock him backward and cause him to drop some coins. He can take advantage of certain enemy attacks however to undergo transformations which allow him to reach areas that he cannot normally get to. For example, exposure to fire makes Wario run around and later become entirely engulfed by flames, which allows him to defeat enemies on contact.^[4] In contrast to its predecessor, the game does not have a time limit, which allows the player to explore the areas in unlimited time, a feature which is incorporated in subsequent installments.

The game features the return of Wario's nemesis, Captain Syrup. Early one morning, she and a few of her soldiers, the Pirate Gooms, sneak into Wario's castle and cause havoc. They steal his precious treasure, set off his giant alarm clock, and leave the tap running, flooding much of his castle. After Wario wakes up and figures out what's going on, he gives chase across the surrounding lands.^[5]

Wario Land II received critical acclaim. Electronic Gaming Monthly gave it their "Game of the Month" award, with their four reviewers praising its vast size, numerous secrets, and varied gameplay. Dan Hsu especially enjoyed how the player character cannot die, only suffer a variety of comic misfortunes which can sometimes allow him to access secret areas, and remarked that "Wario Land II reminds me of so many old-school platformers, yet it's like nothing I've seen before."^[8]

The Game Boy Color version held an aggregate score of 88.04% at GameRankings based on 14 reviews.^[6] IGN insisted that "It's the perfect game to accompany you on a long road trip because of its lastability and replayability."^[9] Allgame considered it a disappointment that it offered no improvements over the original Game Boy version apart from the addition of color, but said the game still held up at the time of its Game Boy Color release due to the well-thought-out puzzle elements and consistently outstanding platforming.^[7]

Nintendo Life, reviewing the Virtual Console re-release, argued that "Big fans of the first game might lament Wario Land II's sudden significant change in gameplay, but if you give it a try, you'll find that it's actually quite good."^[10] In 2019, PC Magazine included Wario Land II on their "The 10 Best Game Boy Games".^[11]

• Official website (in Japanese)
• Wario Land 2 at MobyGames