Hereby, I proudly present:

Here's a short summary of the gamemode. (please, read it all before replying!)
Gamemaster is a platform game, with a twist - you are able to play as the computer (the Gamemaster), trying to prevent the players from completing the level.
As the Gamemaster, you can place enemies, walls, and so on, while the other human players attempt to complete the level. If all the players die, you win. The Gamemaster will stay for one round: after that, a random player will get to be the Gamemaster. You are allocated, in each level, a given selection of enemies, obstacles, and such, which can be placed anywhere offscreen (so the player can't see them being placed).
At the beginning, random blocks will be selected to choose from. Some are more rare than others.
The plot is minimal - you're a computer, running a platform game, and you don't want the players to win. Simple.
It would be 2.5D, like Mario Boxes 2D. There's a simple HUD: As Gamemaster: A part-bin at the bottom, time counter at the top, and that's it; As player: Time counter at top, health bar maybe, that's it. The levels would be themed simple: The main graphics element is grids.
The levels would just be placed separated in one huge map, each time a new round starts, the next level will be used.
The players will probably only have a crowbar. It seems powered enough already, when looking at Sandbox (kill Combine Elites in 3 hits?)
TL;DR: 2 teams: Runners and the Gamemaster. Runners have to get to the end of the level, Gamemaster has to stop them by placing traps, obstacles, enemies where ever he desires. When all the players die, the Gamemaster wins, if even 1 player gets to the end, a new Gamemaster is chosen.
Here's some development screenshots. (click to enlarge)




Gamemaster stuff.



Map update + tile highlighters (for showing where you're gonna place the parts).

You can finally place parts from here:

Getting playable now


Level 2 done, tutorial stuff, etc.






Level 3 and 4 done, fixed the dedicated server for the beta test!










Level 5 done, general game mechanics fixed.






So, what do you think? Maybe have an idea suggestion? A rant perhaps? Post it here!
ModDB: http://www.moddb.com/mods/gamemaster/
I won't update ModDB very often, check this thread for updates instead!
Beta test server has been taken OFFLINE!
RELEASED!!!
SVN: http://game-master.svn.sourceforge.n...t/game-master/
Instructions:
1. Go to your garrysmod folder and then enter the "gamemodes" folder.
2. Make a new folder called "gamemaster". It has to be exactly like that, no capital letters and stuff!
3. Right click and select SVN Checkout (I assume you already have Tortoise SVN installed!)
4. Paste the SVN url above into the first text field thing and hit OK.
5. Get some tea or something, it will now download all the files. Roughly 35 mb total.
6. When it's done, you have successfully installed Gamemaster!
6000 fucking posts. At last.