I think it's a disservice to call it a clone of the helicopter game.
It's a very similar idea, but how the game is played and the consistency of the obstacles are very different.
It's a very similar idea, but how the game is played and the consistency of the obstacles are very different.
The way the game is played is nearly identical. You either increase your altitude or decrease it.
I agree that the consistency of the obstacles is different though.
Also, it doesn't really matter if he did something already done or not. What matters is that he did it in a way that was seen as better by a significant amount of people.