No had a chance to really give the release a thorough going through yet, but so far it seems great - some work still required and there'll always be things that can be improved on but even now it's good as it stands!
Anyway, my first suggestion is based on a change between the demos and the release version. I generally play on my laptop which doesn't have a numeric keypad. This means to speed up and slow down I need to shift into 'num lock' which messes up the other short cuts on the right hand side of the keyboard (including the related pause key). This makes controlling the game speed quite awkward.
Obviously what works for me won't work for everyone else - so any chance of configurable keyboard shortcuts, even just a text file to edit would be enough.
Have fun
Finn