Never mind.. I solved the problem by making the height of vertical gap between the poles higher
But still I think the jump distance of the bird in one click is too high. jumping short distances and clicking many times is much better (I think)
in my opinion the game is made similar to the original game. so speed + jump height are ok. the fact that you scored 2 in 20 min playing is the reason i think everything is ok in this game.
what i think was the reason for such a big success for "flappy bird" is that its so hard to play. because we are talking about a game that has no levels or changes any new situation in the game, you must make it hard. if it would be easy to play then after scoring 50 people will uninstall it.
by making it very hard to play the player will continue trying and trying and trying and trying and trying...
to score more then 2-3 points (in fact i think thats the reason you played for 20 min on a game that your high score was 2!!!
)
rough calculation that should be about 80 restarts... and with smart advertising you can make a lot of money from such games.
that could be a great key for success if you want to make very simple game without any phenomenal graphics.
FORMULA: SIMPLE + HARD = CONTINUOUSLY PLAYING .
btw my high score is 7 (without changing anything in the code)