Do you know an app on Android titled "Threes!"? It is a well constructed puzzle game. It costs about $2 on Google Play.
Google Play: Threes!
The rule is quite simple. You can slide the panels on which some numbers are painted. The panels will be combined when touched each other which have the same number or whose sum is three. The more combined, the more you get a high score.
In spite of its plane look, it is an addictive game.
Soon after the release of "Threes!", several developers created other games with similar taste.
Google Play: 2048 Number Puzzle Game
This is an example. The purpose of this game is to create the number 2048.
Perhaps since it is a free game, it is more popular than the original "Threes!" "2048 Number Puzzle Game" got 11,198 "+1" marks in Google Play, whereas "Threes!" got only 9,232.
The creators of "Threes!" seem to feel not good at the situation. They published a post which reports the endeavor of developing this game on an official blog.
"The Rip-offs & Making Our Original Game"
I understand the emotion of the original creators. Developers of clone games tend to make more profit with less effort. However, I think it should not be blamed, unless they violated the copyright or other regulations. To copy the way of a pioneer to some extent is an effective strategy for weaker competitors, named as "Follower strategy." You can imagine the legal battle between Apple and Samsung. I also refer to Street Fighting Games, whom Capcom originally established with the release of "Street Fight II", and lots of followers created similar games. As a result, this kind of games became a subculture, so that many championship tournaments were held every year.
Therefore, I dare not criticize the way of the followers. Of course, the original should be respected.
Indeed, "2048 Number Puzzle Game" is not bad, even inferior to "Threes!". At last I won the game making 2048.