ACS
(Action Code Script)

It is a scripting language originally used for Hexen: Beyond Heretic game, and then, was expanded to Doom for event, enemy AI and weapons programming logic, structured like C/C++. Scripts work by enabling events during gameplay, creating an interactive environment even in Doom's archaic engine. With simple commands, we can lower floors, open doors, move walls and more. The player and the monsters could have their statistics altered, set up for other experiences, making it easier or harder. Let's get started now, with this simple code:

#include "zcommon.acs"
script 1 ENTER {
print(s: "Welcome to BLAZE TUTORIAL");
}

On Ultimate Doom Builder, we must click on that sheet with a bug (Script Editor) or just pressing F10 to open it.

Now, this is the inner IDE on UDB and write the code.

Let's press F9 to test the map and there it is, the message startup.

As you can see, it is very basic but it works when the player enters to another level and shows its name. Right, let's go for more.