A Violent Act is Going to Feel More Violent If It Is the Player Who Does It.
There is a difference between video games and movies or music when it comes to entertainment art forms. In a video game, the player can actually decide what happens and how it happens in a way that no other medium currently allows. The player may watch a cut-scene where the character on screen kills several people and there’s explosions and action, but it’s a different experience when the player does the actions themselves. There is a certain difference when you carry out the action yourself. Imagine you’re feeling proud about beating a particularly difficult section of the game, but what if you just watched a cut-scene of the same sequence. You wouldn’t feel so proud about it. The same thing applies to your moral compass as you play the game. It feels more real and “icky” when the player carries out the violence themselves, regardless of the reason why. You can use that to your advantage if that’s the reaction you want but keep the player and their state of mind central to the design of the game. You trying to control what the player is feeling, and you need to know in general the range of reactions they could possibly have to the game’s events.
Give Your Character a Signature Attack or Weapon
Sometimes core game mechanics and / or plot points are built around the special abilities of the player character. Imagine the following characters in your head: a viking with a huge axe, a ninja and an amazon warrior with a thick whip. They’re movements, attacks and gameplay would be different and would have to be designed in unique and interesting ways that let the player take advantage of the character’s abilities. Your unique character can have any weapon you can possibly imagine. It doesn’t have to even fit the background settings of the game. Your character could exist in the 1800s with a plasma gun. That might sound silly but a good designer could make that fun. A signature vehicle is also a another weapon / attack that can be included to define your character and gameplay. The vehicle can be the main method of attack or just a backup measure to reinforce the character’s attacks.