I am not sure...it seems some softwares just receive the key you pressed.
For examle, I need to press 'space' or any other keys in some games so I do this:
and when I press " ~ " to trigger, which is picked randomly, the game don't get double 'space' but get the "~" . So the game won't get any type stroke from Keyboard Maestro. By the way, it can still click where ever I want in the games.
Is it the problems of these game or I miss some settings?
(forget about the game and my poor writring
)
Make sure that this macro is available in Asphalt 9. For example, my finder macros are available in the finder application only.
Also, you don't need to type the keystroke "to asphalt 9." You can just have the keystroke be typed normally.
Thank you very much for your help~ 
but eh...it doesn't work...
I tried to make it availabe to asphalt 9 or to global. It looks like the game only receive true hardware keystroke. Even I let the key "space" as the trigger, the game will get the "space" key stroke and boost the car. I don't konw if the game lock the way to prevent behaviors like what I did.
Maybe I just play the game normally 
