You have to click on the nearest red proton (+) before it reach the front.
Be carefull, speed gets higher and wrong tap decreases your score!
I recommend landscape position for play with both thumbs...
Note: It's only beta version, future development depends on public feedback!
Have a fun and post your highscore ;-)
Official discussion here
Changelog:
0.9.1:
Fixed loading issue incidented on some devices causing app crash
0.9:
HighScores are saving!
Difficulty setup
New mode: Accept electrons
G-Sensor and Light can be turned OFF/ON
Improved graphics
0.8:
Initial public release, only concept