- Good idea with the limited ammo weapon... in theory at least. In practice, the alien's logic is often: try to shoot -> no ammo -> nyoron, back to patroling. They do CAN effectively dualwield since Warboy introduced this a few weeks ago, but they would still only meelee if they'd think "I'd rather melee than shoot", NOT "I have no ammo, I must melee". Disappearing weapon might be the solution but I'd avoid making it right-hand weapon, hell knows what happens when the alien is bereft of main weapon but still has secondary. Do not ever try to use logic when dealing with alien behaviour, their AI lacks a proper all-encompassing logical flowchart, as it was built bit by bit by various people (and the guy who wrote most of it is no longer on the team). I don't blame the devs, it just is what it is and we should adapt.
- Acid explosions are indeed (only) possible in Extended.
- Incendiary ammo: they might be weak but they *ignore armor*. You don't need this effect if you can break armor by sheer brute force (Rocket Launcher, Heavy Plasma, even Heavy Laser or massed Laser Rifle fire, it's easy to forget how powerful laser rifles are), so in vanilla they're mostly useless. However, in mods that make the game harder and take away "point at something and it dies" weapons... but like I said, when facing a Sectopod with only a trusty AK rifle and a knife, you HAVE to start being creative about your tactics. Vanilla rarely forces you to think outside the box, as you can always simply saturate the area with heavy firepower
(the exceptions being getting out of Coffinranger, I mean, securing the LZ, and UFO breaching... hence the popularity of mods that allow you to smash/cut UFOs as it saves the pain of coming up with creative breaching tactics, I guess. I'm still somewhat iffy that Warboy broke the vanilla rules and disallowed aliens to use area-effect weapons till turn 3 after his whole crew was blasted with such weapon while they were crowding inside the Skyranger. Weak
).
- The AI never checks for hit chances. Their default firing mode is Snap, although they favor autofire from close by and aimed shot from long distances. It will, however, use non-favored firing modes if the weapon lacks them. Although it WILL happily shoot even if hit chances are 0%; such bad scenario naturally happens quite rarely as aliens can't shoot at targets spotted by other aliens (I am quite sure they COULD do that in vanilla) so they never fire from further than 20 tiles away (their sight range); most weapons retain good hit chances at that range. (This pattern is only broken for Psi and Blaster Launchers. Or so they say, sixth OXCom campaign in and still nobody ever shot me with a Blaster).
- The AI never checks for limited weapon range. If the weapon has a range of say, 7, the aliens will still try to snipe you from 20 tiles away, find that impossible, but won't consciously close distance *to fire*. They can close distance only per their general behaviour OR to charge.
- The AI heavily favors ranged combat. If you give a ranged weapon to a Chryssalid, it will rarely charge with its claws, mostly choosing to shoot. Even when standing 5 tiles away. And it certainly won't agressively try to close the range - only when it thinks it is safe to do so, getting into some cover, reserving TU for reaction fire... As Warboy put it (strange as it may sound), "[Aliens think that] melee is a risky maneuver". They DO sometimes charge, I've checked this in practice, but there's maybe 25% chance of them doing so if they have both ranged and melee weapons, even when standing as close as 5-8 tiles away.
- Side note: remember you can CUSTOMIZE the thing a weapons turns someone into. It doesn't have to be vanilla zombie (although it will always fight on Alien side). I have for example made an (unpublished) weapon that turns enemies into chickens... the chickens are still out to kill you, but they're not very good at it