The weapon is fair in quality, it has standard ammunition, has efficient run speed, but in turn is its small inaccuracy and low damage when firing far range. Because of this, this weapon is quite uncommon amongst players.
The UMP45 is a weapon much like the AUG and should be used far-mid range as its accuracy is somewhat fair. It is useful in large, long distance maps like Harbour.
The UMP45 was meant to appear in beta versions of Critical Strike but was never added until a later version.
In older versions, the UMP45 sounded like the M4A1 but maintained its other physical features.