This should be standard for all games of this sort by now.
(Also, make sure you tell the player that they need to hold down SHIFT to extend. Took me quite a while to work that out.)

First of all thanks for playing! :-)

And sorry about the controls. I removed the tutorial from the newest build :-( You can actually undo by pressing BACKSPACE, but we'll upload a build with a new tutorial soon!

I removed the downloadable version, since it is no longer up to date. I would be happy to send you a new build when a new version is ready. A lot of stuff has happened since this public version including a "How to play" ;-)

Ah, alright. I'm really used to undo being Z in such games; didn't think to try Backspace. And do feel free to send me a new build.