Making jumping puzzles fun
When you think about it, the idea behind a game in which you create apertures in walls to move from one spot to another solving puzzles along the way could be an idea that actually flops terribly. Many games that center around a single novel mechanic are derided as gimmicky.
Mere creativity isn’t enough to make a game fun – the execution has to be on target as well. You can get a sense of this from playing custom Portal levels. Sure, some of them are brilliant and challenging – more so than even the original game – but others are simply not fun. The Portal mechanic is a solid one – and something that Valve worked long months on in order to perfect at a technical level – but the fact that it’s a fun game only works because of high quality overarching design.
Portal manages to be fun because it introduces various skills with the Portal gun gradually and in a fun way. It takes the dictum of "show, don’t tell" to heart, by putting you in front of easy puzzles that you can intuit on your own or with a little help from the sardonic GLaDOS artificial intelligence. You then put those various skills together on the more complicated puzzles, ensuring that you don’t get stuck. It’s interesting that despite the fact that Portal is really nothing but a long series of mobility puzzles strung together, it still manages to be enjoyable. In the history of action games, those that relied too much on "jumping puzzles" were derided for being annoying breaks from the action. The movements in Portal require a fair amount of precision, care and planning, but they aren’t quite as frustrating as similar puzzles are in other games.
Portal also makes good use of physics puzzles, particularly when you’re facing the stationary turrets that bedevil you throughout so much of the game. You can take them out by dropping objects on top of them through portals, dropping the ground out from under them with a portal, by launching yourself at them or even by sneaking entirely around them using a portal. The amount of options that the Portal mechanic gives you for dealing with problems makes it more fun, but it’s still quite difficult to craft puzzles that are both challenging and intuitive. Hopefully, as the player community gets more adept at making maps, we’ll start to see more of higher quality that will help tide us over until the sequel gets released.