1/10
You'd be better off getting
FPS Creator than 3DGM. It has far superior graphics, physics, AI, and everything else. It includes stock media, and there are media packs available both from TGC and members of this community that can expand your options even further. The editor is remarkably simple... pick the room, character, furniture, whatever, and place it on the map where you want it. You can literally make a room with a guy to shoot at in a few seconds, and I made
this game (it's free) using FPSC in only a few days. It includes an intuitive and easy to learn scripting language if you feel like expanding on/ customizing the artificial intelligence, and the engine itself is open-source so you could alter the programming itself and make your game really unique... but you can easily make a game without writing a single line of code or even looking at the scripting language.
And you're even
better off buying
DarkBASIC Professional. It's an easy-to-learn programming language and will allow you to make literally any game you can dream up (well, unless you're trying to make the next
World of Warcraft). Programming isn't as difficult as it looks, and it's a lot more fun than you probably think it is. And if you think FPSC looks cool, keep in mind that its engine is entirely powered by DarkBASIC Pro
. The only thing you're limited by is your imagination. I know that sounds cliche, but it's extremely true... you can make just about anything you can dream up if you learn the language and work hard enough, and nothing feels better than, or is as accomplishing as, releasing a game you programmed yourself.