I’ve actually been a Two Dots player for years and it’s one of my favorite “brainless” games to play. I downloaded Bubble Witch Saga to compare. Off the bat, the launching mechanism in Bubble Witch Saga made more sense for a witch themed game since it looked like a spell or potion shooter. Two Dots hinges on a companion game, so the mechanism of connecting dots together with your finger also follows this more intimate game setting.
In Bubble Witch Saga, there are cauldrons on the bottom that collect extra bubbles at the end of the level that result in extra points as well. The bubbles have fun “spooky” elements inside them, including eyes, mushrooms, and snakes. In one of the higher levels, the goal was to “free the ghost” inside the bubbles, which acted as a fun way to motivate players to finish the level thematically (the ghost was pretty cute too). The inclusion of the main witch character in the level screen gives the game a more personal feel, like you’re working with the witch to achieve the level goals!
In comparison, Two Dots centers around companions traveling the world. I’m on level 1600 right now, and through the many different level groups, you progress through different terrains. From oceans to mountains to deserts to jungles, each stage adds a new type of dot that matches the theme. For example, in the snowy area, there were dots stuck in ice cubes that you had to hit three times before they cracked. Additionally, you get a “postcard” every time you beat a stage that includes a fun picture of the two travelers in the environment. The game goals are similar to Bubble Witch Saga, where in Two Dots, the level requirements change with each environment to match physical elements of the environment. For example, in the Egyptian themed levels, you have to collect a jewels, expand water, and explode suns. In the underwater themed levels, you have to sink a certain number of anchors, and in the space themed levels, launch a certain number of asteroids. The aesthetics of these dots are vaguely different, but ultimately are pretty similar. To collect the anchors and asteroids, both have to reach the bottom of the screen.
Overall, in both of these games, you have to get rid of dots/bubbles. The way these dots are encoded are heavily associated with the theme, mostly in the art design rather than the mechanics. To keep the game interesting, both apply different environments to sections of levels with slightly new variations on the mechanics to adapt to the aesthetics of a new environment.