Great idea & Good pack! if you want some constructive feedback from a designer´s perspective, might be good to change these:
Revive: some gradient in the indication of the player going up to separate from its head
PHD: lighten the icon color, looks too much like its background
SpeedCola: just a little bigger magazine
StaminUp: just make the spiral a tiny but slimmer to resemble the original
MuleKick: make the inverse change, the first gun in a lighter color and the two below it darker (or its ok that way also, no real need to change)
Tombstone: turn it fully upside down would keep its cool and unique aspect, if you dont want, just make the RIP and the Skull icons bigger inside the icon
they also look too big for the game to render, make them all 64x64 or close to that, and export as BC2 (DXT3 Linear) assuming youre using PaintNET to save from PNG the final DDS file.