Draw ‘n’ Merge

Draw a line and lead your ball underground!
The spiked cubes along the way will destroy your balls if the number of balls is smaller than the number of spikes.
On the other hand, if the number of balls is larger or equal to the number of thorns, the thorny cube will be destroyed and the balls will be upgraded.
If there are caged balls along the way, destroy the cage with the balls to increase the number of balls.
Can you advance to the farthest end?