Games [android][beta] simple cube runner game "SpeedCude"

my first game i trying to make with unity

link: https://play.google.com/store/apps/details?id=com.g_games.SpeedCube

actually the main problem currently is that the game is laggy in some devices.
such as samsung j5 (impossible to win level 2) .
galaxsy s4 laggy but possible for playing
onePlus 5 run the game without any lag

if there is any tutorial you suggest to learn about creating and programming better game performence i'ill very appreciate it.

i will try to upload some video later

 

Update : character selector added