If you paused or half fell asleep during the reading of the megila, you have fulfilled your obligation. If you are reading it while fixing the megila and you had intent to fulfill your obligation, you have fulfilled your obligation.

The megila must be written in black ink on parchment with torah script.

Megila 2:3

A person from a walled city who went to a regular city or vice versa and planned to come back before the reading of the megila in the morning,

even if the person ends up not being where he expected to be in the morning, he reads the megila the same as the place he expected to be.

From which part of the megila is a person obligated to read? R’ Meir says you must read the whole megila. R’ Yehuda says from ‘Ish yehudi’. R’ Yosee says from ‘Achar hadivarim haeileh’.