The ESPER Magick System is designed for a modern-day setting where magick is unknown by all except those special select few who secretly weild its power. The rules may be a little vague in places, but that's because the characters and GM should have some wiggle room in their ability to cast spells. For example, the magician using Manipulate Time might speed up time to gain an advantage in combat, normally, but they also might want to age a person or object, or create an illusion that they are constantly not in the place they appear to be, or even read a book in the course of a couple seconds. The magician should definitely discuss their ideas for applications of their spell effects and see if the GM can come up with a way to allow it. It's a lousy GM that turns down brilliant ideas for new ways to use spells!