Doom
You’ll probably get some funny looks if you try to explain to today’s gamers that Call of Duty is just a spin-off of Doom – the revolutionary first-person shooter game for its era that came out in 1993. Doom was the first war game in which the three-dimensional screen is one big field of vision behind a rifle. This game gave new meaning to “violence” an even the gameplay turned killing bad monsters a lot more realistic.