slider and skill check challenges are on the easy side, and its easy to farm them, skill check because you can spam, slider because its just slider. Or maybe I played a bit too much TBS in ITRTG. but slider is very generous here, because if the ball touchess the landing zone even by 1 pixel - it counts. I dont think there is any point in trying to achive high score on leaderboards, since the game is too easy, and there is no way to fact check, besides a screenshot (which can be GIMPed) If you want a meaningfull leaderboard you should look up how other games do that, Its a very interesting topic that involves protection from cheating and ways to store the data in a secure way on the server. You can also use third party solutions(e.g. google play), if you dont have the recources to do so(or dont want to)