Re-add 11 tutorial level, must be beaten to unlock the first 'real' set.
Replace lastRender with an integer tick accumulator in a vain attempt to avoid drift that I thought was caused by accumulation inaccuracies.
Replace bell with winding noise when starting level.
Avoid an off-by-one error when looping tweens restart. It should count e.g. 01210 or 01012, not 012210 or 012012. This ensures each full cycle of the animation, either from 0 to 0, or 0 to the duration, or the reverse, is exactly the length of the duration. Concretely, this fixes the desynchronization between the second hand of the clock and the audio timer in pwl6.
Remove debug timer.