Thanks so much for playing and glad you enjoyed it :) Unfortunately it's not intensional to have them stop spawning and I'm currently investigating the root cause for that bug. It seems to be occurring at slightly different points for different players so thanks for your feedback on when it occurred for you.
Great suggestion on targetting tablets actually, I hadn't really considered that for the jam. I haven't specifically set up touch controls but that should be an easy addition once the upload lock lifts :)