Why does a 2D game like CC lag if there are too many on screen particles, yet a 3D game like Call of Duty (yes, I play the game) with its dynamic lighting, ragdoll physics, bloom effects, fairly realistic explosions and so on doesn't really lag as much. Physics wise, I'd imagine a 3D game to be much more processor consumptive due to the extra dimension full of calculations to figure out, yet quite a few 3D games I've played seem to run much more smoothly even during intense fighting scenes compared to CC.
So why exactly does Cortex Command experience greater lag compared to other more "complicated" games?

Not trying to bash CC here or anything, just interested in how computing stuff works.

Because COD doesn't have physics and CC has every pixel be processed.

The main reason is the difference between their physics engines, and delegation of processing.
Most 3D games offload a huge, huge amount of the processing required to display an image to the graphics card (all of the fancy 3D effects you mentioned), which is specifically designed to be able to perform an insane number of repetitive calculations very quickly in parallel (calculating the new positions of vertices in a triangle from a single rotation operation, for instance).
The actual physics involved, which usually the CPU has to do, are very simple, with the number of objects being acted upon is within a few hundred as opposed to the thousands that Cortex can have flying around.

For instance, in one frame, a 3D game might have three-ish objects to calculate physics on:

• The player, modelled as a box, has just been hit by an explosion, which causes the player to accelerate away from the center of the blast
• An NPC player is running into the blast (modelled as a box)
• The NPC player shot a grenade from his grenade launcher (modelled as a cylinder)

Whereas in one frame, Cortex might have a lot more:

• Each actor consists of 5-8 pieces (head, arms, legs, torso, some attachables)
• Each explosion tends to generate 10-20 particles
• Each explosion particle tends to dislodge terrain particles

All of which must be done on the CPU.

Also CC compared to COD runs pretty damn well, CoD's terribly unoptimized.

Although, slightly offtopic, LAG does have a lot to do with people complaining about actors not moving fast enough or not climbing ladders. When I spent a while getting my computer in tip-top shape, and then running a small map in CC the game was AMAZING. The actors, and the walk paths were much smoother, the weapons felt powerful, and the whole game was just... better.

When CC finally gets optimized we will have a FAR better game on our hands.

Or if computing progresses to 4* what it is now.

I've recently got this and I'm absolutely glued to it - sadly, it asks for a lot of resources, resources my Dell Inspiron 1501 don't have.
Are you guys sure they will optimize Cortex Command? I even started out my own faction mod but abandoned it due to lag, game been sitting lonely for say, 3 weeks and I'm really pissed.
Thanks.

Data has said he plans to optimize some things, but he can only really do so much. You're playing the game on a 6-year-old laptop, and unfortunately, that just isn't the best platform for a processor-intensive game.

Also, CC only uses ONE CORE on your cpu.

Get lots of good ram, and a high clock speed.

maybe they should make it more like terrera if memory servers me right you still had particle but they were bigger and not so many of it, they cover it up with effects such as smoke or big junks of it with smoke trail. so instead of having say 40 parts flying everywhere make it 5 and add 10 smoke effects.