Okay here we go! Just replace the function an add the new var.

Code:
var back_speed = 1; //play with this var 

function handel_timer()
{
	if (spin) //if var spin = 1
	{
		player.tilt += 5*time_step; //rotate the entity
	}
	else // var spin is 0
	{
		if(player.tilt > 0)
		{
			player.tilt += back_speed*time_step;
			key_space = 0; //don't let them use space until .tilt isn't 0 agian
		}
	}
}