I watched the series when it aired, but a lot those elements were laid out in the early seasons and, well, it's been a while! But just to give an overview:
- The Goa'uld are evil megalomaniacal snakes that
take over people's bodies to do, well, whatever they like. They can extend the body's life by a couple of hundred years and give a notable healing boost, and tend to stick around for a while.
- We never really see a large Goa'uld society containing lots and lots of people with snakes in their heads. Not that every single one is a unique and important villain, but they do seem to prefer being mostly surrounded by slaves while themselves being few in number.
- If I recall correctly, they don't need any special implantation procedure, they can just burrow through your back and be done with it.
And they can jump pretty high to get at you in the first place.
- They have access to the host's mind but don't control it: The host is still "there", but completely unable to control anything their body does.
- Removal of a Goa'uld that doesn't want to be removed while leaving the host alive is not possible (well, wasn't, until what's probably going to be the very last movie with the SG-1 cast). I think that if the symbiont *wants* to leave and not kill the body it can do that by itself anytime, though.
There's basically two sorts of "free" Goa'uld hosts, though neither should really be called Goa'uld:
- The Jaffa carry larval Goa'uld in an abdominal pouch. They get the same bonuses to lifespan, health, longevity, etc.. as snakeheads, but aren't controlled by the symbiont. There's huge amounts of Jaffa around, most of them loyal to their Goa'uld masters until the big ol' rebellion that took place over a good part of the series.
- The Tok'ra have snakes in their heads too, but these snakes aren't so much into the whole enslaving humans thing and prefer to timeshare instead. They're naturally incredible secretive and have a we-know-what's-best attitude so that they're pretty much impossible to trust.
Overall, if this is about adding Stargate SG-1 references to zap'm, I'd be thinking about...
- A Zat gun as a weapon. One shot stuns (except when it doesn't), two shots kills (except when it doesn't), three shots disintegrates (except it doesn't and never did in the first place since the third season)
- A staff weapon. Needs no ammo and can cause a lot of scary damage when it hits, but is big, bulky, inaccurate, and shoots like once a second, making it pretty useless if you're trying to actually kill things.
- Sarcophagi. Magical rapid healing stations! (that slowly turn you evil if you use them a lot)
- Jaffas shooting at you with staff weapons. Jaffas shooting at you with staff weapons
all over the place.
-
Perhaps a chance to turn yourself into a Jaffa? The implantation is a bit different for them, see
http://stargate.wikia.com/wiki/Jaffa#Physiology- Even less probably, a chance to get a snake of your own in your head? Thing is, to be true to the original material at all it'd have to be an instant game over if the Goa'uld isn't as cooperative as you expected, and the benefits aren't that different vs. being a Jaffa...
- A pine forest location. Actually, you could probably just forget about everything else. Make an area with trees in it and have the game print "This place looks like a Vancouver pine forest" when you enter. That's the dearest thing to any true Stargate SG-1 fan.
