The one that started it all.
The graphics were incredible for that time, the gameplay surreal and the theme was amazing. The environment was something from outer space, literally. 3D was finally being used as it`s best for the time.
And what makes this game so epic? Starting from the fun. We have never seen such a game where you could kill stuffs and actually feel like we were killing. With lots of blood, lots of weapons and bullets, the game was addictive. I still can play it today without any hesitation. Almost 20 years later!
You had to kill monsters from hell! Yeah, not human beings. Hellspawn! We had 7 different weapons, each one more addictive and useful than the other. Even the fist was a great weapon if you wanted to have some fun sometimes. How can we forget the Big F***ing Gun? Yeah, that was the name of the weapon: BFG.
3 different "episodes", the most epic and influencial of all time was Inferno. Plenty choice of difficulty. You could have an easy time with the easiest and a impossible quest at the hardest (I still have nightmares with the Nightmare! difficulty... couldn`t pass the first stage). And when we had like dozens and dozens monsters at the same time attacking you, and most of time, attacking themselves, that was simply amazing.
We had few puzzles too, that consisted in searching for the keys to open certain doors to continue your fight against hordes of hell. And the bosses of each episode, one more epic than the other.
And of course, we can`t forget about the song. This was probably the top of the sundae. It made the game from very, very good too epic.
Epic game is a game that we can still play today and have almost the same fun we had back then when it was released. And the first Doom fits perfectly on this qualification. The PC version, at least. The SNES version was good too, and the rest was thrash. Stay with PC for the most fun possible.
If you call yourself a fan of FPS genre and never played this before, stop whatever you are doing and play this. If you like games at all, you must try it at least once. One of the best games ever. Top 3, in my opinion.