Sorry, but that’s not a poster, it’s an essay.
Moreover, it is going to be thoroughly offensive to an awful lot of people, thus achieving the exact opposite of what you want it to. It is simply inflammatory. It is also hugely offensive to any other religion and anyone who doesn’t believe in what you want them to believe in.
That kind of vengeful deity is not one I recognise from back when I did believed in some sort of Christian ideology before the motes dropped.
This kind of fire and brimstone approach is definitely not going to appeal to non-believers. It just feeds straight in to exactly why they shouldn’t believe and proves them right.
Personally, I’ll be happy to not make it to any sort of heaven run on such judgemental doctrine and mortal guesswork about what any deity, real or imagined, may think.
That kind of emotive hellfire rhetoric just makes me more sure of a more equitable way I choose to live, that has nothing to do with controlling doctrine and everything to do with other people, fairness and some sense of empathy. What this ‘poster’ preaches is the exact opposite and frankly, it’s dangerous and more than a little bit ugly, in a figurative sense.
The opposite of non-believing us not evil and debauchery.
I think if you want to persuade people that you are right, you need to rethink the entire approach. As a not believer, this just makes me think that you are a little bit deranged and fanatical. I am not saying you are. I can’t. I don’t know you. That poster, however, certainly gives that impression.
I can’t even begin to offer any sort of practical critique about typography, hierarchy, etc, as the entire poster misses the mark of what you want it to achieve. It is more an outpouring of your emotional (and arguably, misguided) doctrine, than it is a piece intended to inform and persuade.
Start again, but iId suggest thinking more like a Christian than a zealot.