I think this works as a proof-of-concept. Use lists to specify x/y coords, costume changes, etc., then you can use the list index to pause and resume where you left off. Each sprite can have its own lists, and I _think_ it'll work with shorter timesteps than one second. This is still in the works so yeah
Original idea is my own; after watching some animations done in Scratch, I found myself wishing for a pause button without having to install extensions.