You determine your entire party's actions at once since these games lacked the ATB introduced in ff4. In FF2-nes, if you cancel and reselect an option, your previous option is still credited towards the levelling system. If you waffle back and forth between trying to choose whether to blast the zombie with fire or cure, selecting, backtracking and reselecting, you'll be credited for casting both black and white magic, and your spell ranks in fire and cure both will increase by however many times they were selected. And your power stat will suffer greatly xD