Sonic Advance is a 2D platformer very much in line with the main series of
Sonic the Hedgehog [ソニックザヘッジホッグ] titles released for the
Sega Mega Drive/Genesis. It features fairly large non-linear stages, Sonic, Tails and Knuckles are still playable with move sets similar to their
Sonic 3 & Knuckles appearance, and ring collecting, emerald hunting, spring hopping, and the act-zone structure are all still here. Theming for the zones will look familiar in places. Runtime is also comparable to individual Genesis titles, with 7 zones + a final boss act in a normal (non-emerald) run that won't take you more than a few hours to work through.
The most notable game play differences are the addition of Amy as a playable character, some tweaks to how the existing characters' moves work, and some further moves added for a touch of new depth to those characters' play styles. While each character is distinct enough to warrant replay, the stages seem designed primarily around Sonic. Playing with other characters will often allow the user to skip a number of the platforming challenges and beat some of the bosses with too much ease, making them better reserved for a 2nd+ play through, emerald hunting, or exploration (there is a stage-select screen). Also important is the new emerald mini-game. Now players trying to gather chaos emeralds must collect rings while free-falling with a faux 3D top-down perspective. I found it very difficult to judge whether I was correctly aligned with rings while falling, and gave up fairly quickly without any emeralds - this is the game's greatest flaw, and will impact any attempt at true completion.
Aesthetically, Sonic Advance meets the high bar set for it by its precursors. Characters' sprites are entirely new, based on their
Sonic Adventure [ソニックアドベンチャー] redesigns. The music is on par with 16-bit main series Sonic titles (excellent), and along with the look of the stages feels very much at home in the series.
Bottom line: a mostly solid but very familiar feeling Sonic platformer. If you've played the Genesis titles (excepting maybe the slower paced debut) or a different
Sonic Advance [ソニックアドバンス] game, how you feel about those will probably be close to how you'll feel about this one.