I'm at a toss up where it's better on the back or front, pros and cons to both.
seems like you'll have more options for credits and such with the egg on the front and I like the fact of time line...the egg comes first and grows into...Alien.
but then again the main charater is the Alien, but the egg on the back reduces the layout options.
hard for me to decide, it would depend on the other layouts (credits,etc)
but if I had to choose right now...I'd be sightly over the the egg on the front cover.
sorry for the long winded answer...lol