In 1986 Bubble Bobble introduced the two small dragon characters, Bub and Bob, and brand new play mechanics, with participants licking enemies by trapping them in bubbles and then popping them. Although the puzzle-action game can be beaten by clearing all 100 rounds, it also incorporates private elements such as not being able to get the "true ending" in single-player mode; concealed commands that lead to secret rounds; and a ton of unique items. These atmospheric conditions are some of the game's most unforgettable and crucial features. Each round even has unique air currents that are not visible, so bubbles rise in irregular patterns. Aspects like forcing participants to realize and use these unique patterns while acting help make this a radical game that is extremely fun to play.