The first spin-off game of the Sonic series to mix platforming and role-playing game elements. It was the third and last game in which Tails is without Sonic, the first two being Tails and the Music Maker for the Sega Pico and Tails' Skypatrol also for the Game Gear. The game does not follow the plotline of many other games in the Sonic series, and the game's plot is different in the Japanese and Western versions of the game. In the game, Tails must save an island from destruction by the Battle Kukku Army, an army of birds, while at the same time obtaining objects such as various types of weapons and Chaos Emeralds that he finds during his passage. The gameplay is unlike that of many other games in the series, consisting of slower travel, and more time is spent searching for objects to use later on in the game, rather than simply running through levels.
Contrary to the classic speedy gameplay in the Sonic series, Tails Adventures is a puzzle-based platformer with a strong emphasis on item collecting and backtracking, like a side-scrolling action RPG.
Tails can walk, jump, duck, look up, fly, hang on ledges, and can solve puzzles and defend himself with a range of different items, such as Hammers, various types of Bombs, and medallions bearing other characters, which allow him to perform additional actions, such as Spin-Dashing or punching enemies. His health is measured numerically by a Ring Item Box at the top left corner of the screen. HP is replenished by collecting Rings, which can be found by blowing up rocks or defeating enemies. He starts with 10 HP, but that number maxes out at 99 when all six Chaos Emeralds have been collected. His air time is limited by the flight gauge, which starts at about 3 seconds and maxes out at about 15.
The Japanese version of the game has a different plot line than the Western version of the game. However, the difference ends in the manual, because both the Japanese cartridge and the Western cartridge are identical. The language the game is in is automatically set to whichever region the Game Gear unit is in. The Japanese version of the game has a more complex version of the story than the Western version, but besides this difference, and the names of various items in the game, both are identical.
Source: Wikipedia, "Tails Adventure", available under the CC-BY-SA License.