I thought you had some really cool things included here, particularly starting in medias res. But it also reads just like any other on-the-rails zombie story, right? Am I missing something here?

And what does the "cleansing" sign mean? Because that is obviously not something our POV can know anything about, which means you're breaking POV every time you add that sign. You're writing in close 3rd, remember.

Why is it important for the reader to know how many thousands/millions of people die? That's kinda understood if it's an apocalypse, right?

It's a rookie mistake to use sweeping big picture descriptions during large battles and world-changing events in prose. Just focus on our main character and let everything else come naturally. Your writing is pretty good, have more confidence in yourself.

Keep up the writing!

An interesting story marred by clumsy punctuation and spelling errors, which suggest that you did not take the time to read through your work before submitting it. It would also appear that you did not thoroughly read the submission guidelines as there are presentation issues too...

Your story-telling is good, but at times a little rushed which leaves gaps in your plot and narrative. Overall, though, not a bad beginning. Take more care with future chapters and you'll produce an engaging, entertaining story.