Balloon Trip starred Baby Mario and seemed to have been based on the early parts of Super Mario World 2: Yoshi's Island's story, focusing on Baby Mario plummeting towards Yoshi's Island after being knocked away from the Stork by Kamek. In Balloon Trip, Baby Mario is given three balloons to hold him aloft in the air, though touching an enemy can remove one of these balloons. If Baby Mario loses all three of these balloons, he will be snatched up by Kamek and presumably be taken to Baby Bowser's Castle, changing the course of Mario's life. However, the player of Balloon Trip may use the stylus to draw clouds across the sky as to lead Baby Mario away from enemies; if Baby Mario touches a cloud, his fall will be affected by it in a realistic manner (therefore allowing players to guide Mario out of enemies' paths). Players can also draw circles around enemies to encase them in bubbles, turning them into coins. (Later on, in Yoshi Touch & Go, these bubbles could be dragged and thrown with the stylus, though it is unknown whether such a feature existed in Balloon Trip.) Leading Baby Mario to coins or rewarding him with enemies-turned-coins was the true goal of Balloon Trip, as collecting coins was the only way to earn points. If Baby Mario survives the skies for a set amount of time, he will eventually find his way to the ground, where he (once again reflecting the story of Super Mario World 2: Yoshi's Island) will be caught by a Green Yoshi (thought to be Yoshi) and the player will be congratulated for their score, ending the demo.
 History and development
As stated above, Balloon Trip would eventually be released as the full game Yoshi Touch & Go. During the days of Balloon Trip, it would appear that Yoshi Touch & Go was already planned (though then unannounced) to eventually become a full game, making Balloon Trip an example of the rare case that is a tech demo previously planned to be released as a full game. It would actually seem that the Balloon Trip tech demo came somewhat late in the early conceptual planning stages for Yoshi Touch & Go, at a time when it was not yet completely decided whether the final version of Yoshi Touch & Go would be for the Nintendo GameCube or DS. After Balloon Trip was shown at E3, Yoshi Touch & Go's programmers decided that there was "no turning back" and expanded upon Balloon Trip for the Nintendo DS rather than the GameCube (whose version they did away with), eventually creating the final Yoshi Touch & Go current-day players are familiar with.
 Differences With Yoshi Touch & Go
More or less all of Balloon Trip's basic gameplay survived into Yoshi Touch & Go, although this gameplay actually existed as only one half of each of the final Yoshi Touch & Go's one-player modes. Specifically, Yoshi Touch & Go added a whole new section to each of its modes (save for the multiplayer Vs. Mode): After Baby Mario lands on Yoshi's back (at which Balloon Trip would have ended), Yoshi Touch & Go places in a whole new playable segment involving Yoshi, which abilities such as Jumping, Flutter Jumping, and throwing a limited supply of Yoshi Eggs, traversing across Yoshi's Island and avoiding or defeating various enemies, several of which were not even seen in Balloon Trip or, for that matter, Yoshi Touch & Go''s own sky segments. It is possible that these ground segments were derived from Yoshi Touch & Go's canceled GameCube version (which was said to involve Yoshi protecting Baby Mario) or other elements from Yoshi Touch & Go's early planning that were not involved in the Balloon Trip tech demo.
Aside from this noticeable gameplay addition of ground segments, several other, smaller differences were done from Balloon Trip to the final Yoshi Touch & Go. Several enemies' attacking patterns and turf were changed, with enemies such as Fangs becoming exclusive to the ground segments and foes such as Boos being completely removed from the game. (The Boos' attacking patterns were seemingly taken up by Solo Toadies in the final Yoshi Touch & Go.) The red arrow used in drawing clouds was also removed and given no replacement. Though Balloon Trip's basic art style survived into Yoshi Touch & Go (despite being elaborated on in fields such as shading and attention to detail), several character designs were completely redone from those of Balloon Trip before Yoshi Touch & Go was released. On a similar note, most characters and objects in Balloon Trip were also given different animation and the final game sported a new HUD as to reflect its various new gameplay features. Perhaps strangely, most of Balloon Trip's sounds were used in the final Yoshi Touch & Go seemingly unedited.