Unless you have a mod messing with the upgrades or didn't apply them correctly, the difference should be pretty obvious.

I don't know that the weapon upgrades actually do anything. It still took the same amount of shots to kill the 2 enemy types, so I got that "Gallery II" map and tried shooting the targets before and after adding various upgrades and didn't observe any change in damage or rate of fire. The mag size upgrades did seem to work.

Oh fudge yeah thanks!

It's a button. You can see the hallway where it's used just outside.

What is that white pill looking thing in Projection from Engineering for?

blue is rate of fire (bullets per minute)
red is damage
yellow is capacity
green is recoil

Cadencia de fuego.

¿Qué es lo que hace el azul?¿Qué es lo que mejora?

Yes to both. It's how the game references the stats internally.

Is the green crosshair symbol representing recoil? And the blue... is RPM?