I can't wait for Portal. It looks really fun and imaginative. So, I decided that while I'm bored, I should try to make something like it using the Source SDK. I don't want to make it exactly like Portal, but I would like to make some type of first-person puzzle game. At first, I thought about simply trying to solve puzzles with the gravity gun, but that isn't really anything new. But, I can't come up with anymore ideas. Any suggestions would be greatly appreciated! :D

I'm not sure I follow what you mean. You want to make a First Person Shooter with environmental puzzles instead of shooting enemies? I've never played Portal so I'm not sure what that is.

I never said "first-person shooter". Portal is a game that hasn't been released yet in which you use two portals to solve puzzles and navigate obstacles. It's made by Valve and powered by the Source Engine.

Anyway, you are correct in that there won't be any enemies. I'm just looking for a twist on normal environmental puzzles as Valve did with Portal.

If you want something like Portal, make a game where you have to be in a closed room and there's no obvious exit in it - the goal is to find it. The player has to do that by deciphring messages that tells you where exactly it is.

By knocking on the wall to see if it makes a different sound, noticing if the color is different at any part, going through a maze, following a noise, stepping on the right sequence of buttons, and what ever else you can think of, you can disvocer the location of the door/exit wall.

If it's like a maze you can just put a door at the end, and if it's something else, or even at the maze, make it so that you have to launch a magic spell on the spot on the wall so a portal opens and you go to the next room.

And on, and on, until the end of the game.

What do you think of it?

I like that idea. It also allows me to make physics puzzles and things. I actually never thought about hiding the door, but simply making it impossible to reach at first glance. But, hiding it could make the puzzles more interesting. I've read in various game design topics that putting the player in a confined space with no clear exit can really make them get frantic. :P

I'll keep that one in mind. Any other suggestions?