There is an ending for the baby, if you do not get any powers asides from regeneration and the standard door opening, protect thebaby the whole time... you get the pure ending (good?).
another ending is the Vampire ending, you corrupt everyone befriend/bite etc, and beat the boss without the SYMBIOTE power.
Final Ending is the Symbiote Ending, where you are infested (the anal creature), you eat everyone and everything... become strong, and just head to earth to corrupt it further. you are no longer you etc in that ending.
the game is absolutely ABYSMAL for story/plot. its more or less people wanting it for the art/video cinematics at this point.
The creator says the dogs tear your throat out (in the beastiary) and the spiders dont.
The way you get them to not kill you is to just crouch and crawl, let them have your way with you...
Its a pain in the ass of a game honestly. it needs a lot of gameplay mechanic overhauls to even be worth the indivudal to play unless you prefer the problems of notknowing where you are, what to do... or really how to do anything.