The animation problem represented by the rocket (mentioned in the previous post) led me to start tinkering with the Ticktimer() thread. In particular, the amount of sleep() I give it. Allowing the timer less sleep (reducing from 80ms to 16ms) gave the animation a superb boost, and the jerky animation disappeared altogether. Of course, the emulator with debug (on PC with Android Studio) still moves pretty slowly, but running on a naked Android device is highly efficient.
Pretty soon, I'll have to implement a "disable touch response" system, so that the user can't do anything during an animation that has to run to completion.