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.
Mileena. Though always violent, bloodthirsty, and sadistic, Mileena is also normally shown to me too mentally immature to know any better. Here however she is more mentally stable but no less evil and sadistic, being a psychotic mass murderer who kills in Shao Khan's name with barely disguised relish, also killing Kitana's father and after beating Johnny Cage demanding that Kitana finish him. When she refuses Mileena savagely beats her with sadistic glee and makes it abundantly clear that she's had murderous feelings towards her sister for some time.
Quan-Chi, who disguised as Sub-Zero slaughters Scorpion's entire clan, including his wife and child son, and then after killing him tricks him into thinking that his best friend betrayed him, subsequently turning him into his loyal minion that then kills the real Sub-Zero.
Narm: According to viewers who know Japanese, the segments of the Scorpion/Sub-Zero episodes spoken in the language were laughable.
Nightmare Fuel: Cyrax and Sektor's transformation into cyborgs pretty much invokes this
Special Effect Failure: Live-action Mileena's Tarkatan teeth only appear when the scene calls for it. This is especially evident in Legacy II when the camera does show close-ups of her face and only her human teeth are bared.
There have been other occasional examples of this besides, which has gotten some ire from viewers. However, there has also been a lot of...