Am I missing something?

[Knavenformed]

After the Geonosis section and getting to the ship missions, I get introduced to the lizard enemies and need to escape through the vent, after that I come to another corridor with a 3 lizardman ambush.

Thing is they take a magdump to take down and are fast enough to back me up to where I came from.
Am I meant to use the grenade launcher there or is there a headshot mechanic for normal enemies in this, SBDs do have some weakspot interaction, but this section of the game feel way overtuned if the rifle is the intended weapon there.

[=CrimsoN=]

Yeah, this is a common gripe. The lore explanation is that Clone weapons are suited for droids. They fire an ionized blast that messes with the electronics in droids, which is why they melt the regular b1 battle droids and do decent damage to SBDs. But are practically worthless against flesh opponents (like Trandos).

In terms of gameplay, you're better of knifing the trandos early on. Soon you'll encounter trandos who use blaster shotguns. Pick one of those up and it will help you for the rest of campaign until you encounter trando elites. The blaster shotgun is devastating though and can one shot the regular trandos.

[Sargon The Grape]

Headshots do more damage, yes. It won't take very long for you to meet trandoshans who drop their weapons, and you should pick these up at every opportunity. At first it'll be shotguns, and later sub-machine guns. Their own weapons work better against them.

Generally speaking, the best way to deal with trandos is to charge at them while shooting them in the head and then knifing them to death. The only exception is the trandoshan elites, who soak damage like a super battle droid and have a chaingun that can kill you pretty quickly. You'll want to grenade them.

[Boreout [Aut]]

Flashbangs and even emp grenades work as they electrify them for a short amount of time.

Don`t hesitate to use your grenadelauncher when trandos are rushing towards you , some objects in the game explode , like red orange barrels, white gascontainers and the consoles do electric or exposive damage when shot at.

Trandoshutgun for trandos , blaster against droids , the minibosses require heavier weapons and trategies.
The best alien weapons are the trando HMG, the geonosian laser and the trando shotgun.
Trando smg is a bit disappointing and the bowcaster is like a weaker sniper when not charged.
For high damage the the trando concussion rifle kicks ass. The wookie rpg is really rare and a bit overkill for most enemies but will autoguide when fully charged.