I haven't got the 42-move solution yet, but Play Ball can be done in 16.

LL: I think (but can't check for certain) that you have to get the left-hand drop in front of the red spike before you push the wooden spike in from the right. You then push the wooden spike back over to the right and the gem is in one of the blocks to the left of where it stops.

It is possible (at least on a Galaxy Note) to get the perfect score -- you just have to be lucky/careful (I think it took me two or three attempts once I'd found the correct solution). However, since it's presumably some subtle timing issue in the game's mechanics, it's possible that on some platforms it may never be possible.

Also, being able to see your best-so-far score (perhaps on the "Pause" screen).

Resist introducing any tight timing -- the couple of times in Reflect where you had to hit something into the path of a looping drop were fine, but a lot of the charm of Quell is that you can calmly contemplate solutions without having to move dexterously.

Would be nice if it could remember the players' solutions -- a few times when going back to a level to get "Perfect", it took a while to remember how I'd tackled it. Seeing a replay of my best solve so far would have been handy.

Maybe when drops combine they could become larger/heavier and could then break certain elements.

Drop runs over a patch of sunlight and breaks ("refracts") into two or more rainbow coloured drops ... certain pills can only be collected by a drop of the right colour.

Thanks for these... gives me some more to aim for!