Nice concept! I really like the idea!
Here's what I think - I'd go for the zoomed one, mainly because it allows you to pay more attention to the creatures that actually challenge Godzilla, instead of Godzilla itself.
Full image will make Zilla the main hero, while zoomed focuses more on the kids. I kinda feel that suits this months theme a bit more!
It's also funnier! There is much more to play with there. Some design relation between all of the kids, expressions the kids and people make. Generally, much more potential to do something fun.
Of course that is my way of thinking, you are free to think differently!