I'm not coming from weapons firing experience, I'm coming from gaming and game design experience. Weapons that have a metallic sound in the games I've played sound heavier to me, as if the mechanism to move the ammo can be heard over the explosion it makes the gun seem just as powerful as the shot it fires and the added bass allows the player to feel the shot as much as hear it. The other way to go is the way of sounding like close by thunder for more energy based weapons.
The issue is, a lot of people have guns. They've fired guns. They know what a gun sounds like. It irks them to hear a gun making a sound that is very much not the sound of a gun.
And the actual sound made by most guns is awe-inspiring anyway, so if it's a gun why not stick with the sound it really makes?
As far as stun lock, the trick would be to blend movement with the hit animation (based on where the shot lands of course) then follow up with AI for the unit to find cover using a damaged state movement (like a desperate dash or a lifeless dive for cover). Its important that the timing between shots and the movement for a character to evade is well spaced to ensure pacing. If the weapon is meant to feel strong, then characters and environment should react appropriately to the weapons power. The numbers offered above seem useful if those are the animations you want to use. I've always hated the flinch animation most games use when characters get shot. When I unload a light automatic into an enemy and it does two or three flinch animations then a death animation, it drives me bonkers. I like to see characters(who still have an intact brain) think about the damage I just did to them and move appropriately to the pain and suffering I've cause by using such a sloppy weapon. Seems like every enemy in every game out there is morphed up and tweaking on adrenaline, its boring. I want to see the effects of my weapons and the only time I don't want to see it is when I've hit the mark. If I've done my job, the enemy crumples.
There's a lot here that just doesn't fit the kind of game this is. Killing enemies here takes time, the fights are longer and recovery from your injuries is so slow you can't even really consider it. Your enemies are dangerous for a long time, even after being fatally wounded, in much the way a real living thing it. You may, for instance, see a bear a hundred metres off, fatally wound it with your rifle, then get mauled to death by the dying animal before it bleeds out. In a less extreme (and much more likely, since a bear is a big fast clumsy thing that can't slow down or turn easy and is quite avoidable on foot, not to mention you have a full magazine if you have any sense) example, you might shoot a trog in the head with your pistol, then end up wrestling with it until the blood loss gets to it. This fundamentally changes how the game is designed, and how the animations really reflect what your doing should change with it.
With particle work, all that matters is that the player thinks it looks right. This will all depend on the weapons design. A couple games that really sell the "feel" of powerful weapons are Gears of War(obviously) and Warhammer Space Marine IMO. As for heat warble, smoke and the likes, each gun should be just as much a character in the game as the NPCs and enemies the player faces. Think about each gun and its history, give it meaningful interesting and useful quirks, even with the most standard weapons, it'll be worth it.
Every gun is already meant to be meaningfully different, but unlike Gears or Warhammer we can have have powerful and unique weapons that are NOT ridiculous.
As for knockback it depends on what the weapon's ammo(type) is doing against the type of surface its hitting. Obviously penetration is only going to create knockback if the character becomes mindful of the shot, possibly falling back after realizing they are beaten. But a few successive rifle shots against an armored target should push them back (especially if the shots are high). Even grazes and shots that connect with the shoulders should cause characters to reel back to A)create a smaller silhouette to land a second shot on and B)to inform the player of where the shot landed.
No. It. Doesn't. Any weapon with enough momentum to send somebody back at any significant speed would do just as much, realistically by far more, to its user. There is no push when hit with a bullet, even if it transfers every scrap of momentum, because if there was enough momentum for it to push a target the weapon would be unusable. Spreading it out over several shots doesn't make this any less ludicrous from a physics perspective. The ONLY weapons you could realistically knock people around with are melee weapons, and even then it's not likely since you'd need to throw enough momentum into a hit to knock an enemy down, and that means getting yourself moving pretty fast, which is hard to pull off since you telegraph your attack so far in advance no enemy could fail to get out of the way.
This is all just visual feedback. The character could flash red if you want but in the end the player needs to know they've connected their shot with the target and a knockback allows the pacing to change. As the player checks whether the shot has finished the job.
You seem to be neglecting just about everything about the game to make this argument for knockback. This doesn't fit at all. Knockback conflicts with the game's combat style, genre, tone and purpose. Knockback is flat-out wrong for this game in every sense. There's no way it benefits the game.
Key word in video games in my opinion is video. Successive images to depict movement. The more you explore movement and its meaning in your game the more you're exploring the element that separates video games from any other number crunching card, board, dice games, etc.
This is a complete non-sequitor.
