Ok guys I just recently caught up with the Manga and came up with what I think is a pretty quick but solid theory on everything. I went through the Manga pretty fast so if I'm missing something or it doesn't make sense let me know.
This is probably full of holes, but almost every would make sense under this theory to me, unless I'm forgetting major things.
starting with the gorilla titan. I think it's one of the original titans that humans fought against how ever many years ago. To retaliate, the humans created humans versions of the titans, but the experiments went wrong and the human titans were wild, uncontrollable, and started to eat humans for whatever reason. To cover up the mistake the Gov tried to erase any record of what happened 107 yrs ago before the wall went up. (I'm still tryna fill out the start of the wall). The royal family was behind most of these decisions and decided to keep citizens in the dark ages by using fear tactics and hoarding technology within the most inner wall. In the present day, someone (the gov maybe) is still experimenting with human titans, hence the village inside the wall with titans. Annie, Rainer, and Bertlot were more advanced versions of the experiments, BUT Eren is the perfected or most advanced version that his father was working on. He used that version on Eren before the shyt went down. Now this may explain why everyone is after Eren. If he is the most powerful titan, he would be an asset or threat depending on the side.
Levi the gawd so cold wit it
shyt was revealed in the previous chapter but i aint seen nobody really mention it, shyt came outta left field and took me by surprise, and then the nikka who showed up with the guns got that same last name too 
.... where the fukk is season 2 