The checkpoint system is definitely on the roadmap, but just has not been implemented yet. I hope to pick up the pace for these kinds of features soon.
Regarding you running it on your phone, I'm not entirely certain. Glad to hear that the newest update is working though, so I'll try to ensure future updates maintain this functionality. I will confess that this game is being focused with PC controls in mind - I don't have the time to test phone controls in addition to everything else. If my SubscribeStar does well and enough people ask for it, I will add phone support.