Ive played through Resident Evil 4 about 30 times, easily, and I can't believe that this is the first time I noticed this.

The Ganado that you meet in the cabin at the beginning of the game, the first Ganado, and the Ganado that attacks you in ch 1-2 are the same.

Relevant cutscene is at the 1:41 mark.

Now, I always wondered why the ganado that attacks you after Leon loses his jacket was always shot to shit, and after completing the game I always chalked it up to Ada trying to kill the zombie before he could get to you and failing, but as I have recently watched a playthough of Separate ways, I found that this was not the case.

So why is the Ganado shot up? I do not have objective proof, being documentation that the two are the exact same, but follow my inferences on this one.

1. Its the same character model:
Yes, this is obvious, but the easiest way to destroy this theory would have been if the character models from the first Ganado and this one were different. So, with it, there is a coincidence that could be made, without it, there is no connection.

2. He's shot up, but did not dissolve.
What did Leon do to the first Ganado he saw? he shot him. He also shot up other Don Jose character model Ganado's through the Pueblo as well, but unlike most of those, the first Ganado did not dissolve, just like the rest of the Ganado's in the first segment of the game.

3. He's aggressive:
This is a bit of a leap, but bare with me.
When Leon and Luis were captured, Chief Mendez left a note says he instructed the two prisoners to be moved to the valley and not be touched, as all they had to do was wait for their eggs to hatch. So as we see, all of the ganados complied... except for one. Why?
I have a theory that plays into the fact that he was wounded and his special nature. Being possibly the first line of defense of the village besides possibly wolves running through the forest, it would make sense the first person an outsider would encounter would be extra violent, possibly by command or breed of the parasite, to outsiders. We also have some understanding of this through the bodyparts he is burning as well as the box of skulls he keeps under his staircase.

So once he has been taken out, given enough damage that a normal Ganado would have perished, this drive to fulfil his lords command could possibly raise him from the dead and keep on fighting, either ignoring the Chief's command or not properly receiving it due to the wounds he received not registering the new orders, which dictated him he grab an axe, walk past his sleepwalking fellows, and try to kill Leon and Luis.

So yeah, that's why I think that the First Ganado in RE4 is the same one who tries to kill you in ch 1-2. And it only took me 10 years to figure it out.