Mobi.

You need to guide the ball from the start circle (solid) to the goal circle (hollow) while collecting the trail marks by tilting your device. You cannot do other way, you have to go through all the trail marks in order to complete and you have to reach the goal to complete the level. Trail marks worth points but the value decrease by time, in steps, after an initial delay, so be as quick as you can! Look out for the reward and penalty points along the way, collecting rewards and avoid penalty, preferably. : )
The game starts easy but will get hard gradually as you go to higher levels, introducing complex trail, quicker ball, rotating trail and zombie balls that slow you down if touched, but do not worry, you will heal in shorter or longer time.
Each level has maximum points available to collect and you could check how well you performed collecting by checking the percentage value.

Have fun! : )

Tips:
The orientation of the device at the time pressing the start button will count as horizontal so you are not obliged to hold the device horizontally to play.
Holding the Score title three times in quick succession will reset all scores collected on all levels, effectively resetting to the after installation state. Use with care if you do not want to loose all the hard earned points prematurely!