DOOM is a very popular video game created by Id Software and released in 1993 first for PC and then for many other platforms and consoles, including the Super Nintendo.
A videogame that, 
together with the equally mythical Wolfenstein 3D, is considered (rightly) one of the most important first-person shooters in the entire history of gaming. In DOOM we find an innovative use of graphics 3D, an overall simple and fast style of play and a rather high rate of violence, which has made it very popular for years.
It still is popular, more than 20 years after its release on the market. Played by millions of videogamers, DOOM boasts numerous sequels: from Doom II: Hell on Earth in 1994 to The Ultimate Doom in 1995, through Final Doom in 1996 and Doom 64 in 1997. The saga ended in 2004 with DOOM 3. Here are some useful ones tricks for the SNES version.
CHAIN GUN AT LEVEL 2
At the second level go left and then left again; look towards the left wall and you will find a peeling wall. Open the door and press the button, then go where you should get the red key (room on the left): an open area will open, always going forward you should find a Chain Gun.
SECRETS LEVEL 5
Head to the bridge where you should go to get the fallen key; on the left side is a brown wall, open it and grab some good stuff and a rocket launcher.
THE STAR
Grab the blue key, go to the tower on the right where the IMP is shooting at you. Go to the tower, lower it and kill the enemy, then raise it, look at the wall on the right, open it and you will find a secret room. (The star will bring you close to the start of the path!)
SECRET ROOM
At first go up the stairs, shoot the toxic barrel, open the wall and you will find a lot of useful items.
SKIP THE LEVEL
In Shores of Hell, on the second level, make your way into the room between some Imps. Kill them all and head to the room with the green monsters: on the right is a corridor. Follow it until you enter a room with a demon, to your left is another corridor that leads to a room with 2 types of ammo. There is a sign that says 'EXIT'. Go there to skip 2 levels.
