For both Game Art and Animation and Game Programming, what exactly sits in your portfolio when you go to find a job should be somewhat obvious. With Game Design it can seem like things appear just a little bit murkier. You learn early on that much of your job as a game designer is documentation. Then you start learning mechanic, concept and level design; all of which can be substantially more visually exciting to look at but not always. Plus with level design, you can't always expect that developers would have everything you need them to have in order to play your level. So what do you do? What do developers really want to see from Game Designers? Well we recently had the opportunity to speak with developers from EA and Blizzard and they revealed some fairly enlightening things.
Videos - So you have a level to show off your design skill but you can't be sure they could play it if you put all the files on your portfolio website. Nor could you really be sure they would want to download all the files they need to play your level. Videos (NOT SCREENSHOTS) can do a fantastic job of showing off a level in it's entirety. It can show how the level is laid out, the set design, any mechanics you may have developed or what you did with the mechanics that were already present which can almost be more important.
Board Games - Developers (or at least the ones at Blizzard) want to see more board games in game design portfolios. Why? They're typically something you have to build in it's entirety. It shows off your abilities to design mechanics, and direct gameplay. Not only that but the files needed for board games are small, typically only a .jpg and a word document. So developers can easily print out your game and try it for themselves. Part of the key to being a good game designer is communication and if they can play your game without you there to explain anything or clear anything up then you're in pretty good shape. You can even test this out at home by giving the game to people who don't know how to play your game and just watch them. Absolutely refuse to answer any questions they have unless they're really stuck or until the game has ended. If they get stuck that alone tells you that your directions aren't clear enough regardless of what their question happens to be. Some people get trapped in this loop where they decide that "people are simply too stupid to play my games properly" and frankly if you ever want to be a designer you have to let go of this thought.
No Game Design Documents (GDDs) - Remember how I said that being a designer is a lot of documentation? Well this would be the Game Design Document that will have inside of it, everything you could every possibly need to know about creating the game. From various balance iterations, to gameplay mechanics and beyond all of it should be held in that document. However, frankly developers won't read them. Besides the fact that these documents tend to be very large, just reading them can put a developer at risk. Plus every company tends to organize their GDDs differently for different reasons so if you were to get a job they will teach you how they want a GDD organized.
Having a good portfolio and knowing what to put inside of it can be one of the keys to landing a job. There's no one right way to build a portfolio but these are some of the tips I've received and hopefully they will serve well when trying to find a job in the future.