This is freaking sweet! If you want smoke continually on your screen, in the configure screen, check "Point Source Mode" and a plume of smoke will continually rise from the center of your screen.
I've got quite a lot to add to Smoke Play to get it to where I want it. I've been messing around with some settings and superficial stuff for about a week so I thought it just needs to get out there.
My ideas for features are:
a settings activity where you can up the detail and iterations on the fluid solver for more powerful phones
expose all the smoke (or fluid) properties to be customisable
define some cool pre-sets
coloured smoke that mixes (have this working on my laptop)
continuous auto-sources of smoke
objects (draw shapes) in the path of the smoke
calculated objects field from the homescreen icons (smoke collides with your icons)
an auto-config activity which scales the detail up or down to optimise quality on all phones
maybe put an ad in the settings activity
I'm not sure what order I'll do things in. I think some sort of settings screen will be up next.