These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Darkest of Days
Game Breaker: Extended mags and fast reload upgrade works this way, especially for pistols. You can behave like you are wielding full-auto weapons, while everyone else is with muskets or bolt-action rifles.