The easiest way to contact us is via the built-in chat system.
To start this, return back out of this answer, and then tap the speech bubble icon at the top-right of the screen!
( On some devices it may say 'Message Us' at the bottom of the screen instead )
Your messages will come through to us, and we can reply back to you within the game itself.
We're not always online (there are just two of us at Astraware!) so please don't expect an instant reply from us, but we do try to get back to you within a day (or less!).
When there's a reply from us, you'll see the messages icon in the title screen of the game changes to have a number in (which is the number of new messages.) Just tap on that to look at the new replies!