Dragon's Curse would certainly have no place on any sort of "unappreciated gems" list; it's received far too much recognition to pass for a "sleeper." Still, speaking in purely relative terms, I'm a little surprised that it isn't discussed more often amongst Turbo fans, as it's a very charming and extremely well-thought-out sidescrolling adventure game.
A large, secret-stocked realm for players to explore and a main character who transforms into various creatures are DC's finest assets. Some shapes come with expected proficiencies--that Piranha Man swims, Hawk Man flies, and Mouse Man sneaks through small openings should come as no great shock to anyone. But the rodent can also scale walls and tread upside down on ceilings, while Lizard Man breathes fire and Tiger Man attacks with sweeping sword swipes. Comfortable controls make even the more routine actions enjoyable, and putting all of your available skills to good use can lead to some astounding discoveries.
DC's appealing sounds and visuals contribute to its overall air of lightheartedness. The soundtrack, one of Duomitri's favorites, is generally fast paced and upbeat, while the graphics are quite colorful and cartoonish.