I have added more levels to Orange Car!, and I plan to add more along with the below additions:
1 ) Personal high scores for each level
2 ) Leaderboard page accessible from main menu (will show overall high scores, regardless of level)
3 ) Fullscreen and mute buttons on main menu
4 ) Adjust speed and frequency on certain levels
5 ) Possibly change background music according to level
Let me know if you have any other suggestions…