Algorithm design? That's my weak point
Anyways, AGI and AGS're the easiest ones. They're fairly straight-forward when it comes to design: Create backgrounds (for AGI under a special drawing program for it, under AGS, you can use other tools too), create animations, music and combine them all in the studio, while coding them. I don't know much 'bout AGS' programming language, but I know that AGI uses a step-in for a step-in of C++ (that other step-in being SCI, which's like AGI, but with better graphics and the point'n click/pop-up parser). The learning curve of these languages is from a day up to a week, depending on how well you learn. I know AGI's best learned through looking at other people's sourcecode and reading the elaborate help-file. Same goes for SCI.
Outside these three, which're more for making adventure games (AGI and SCI for older and newer Sierra-style, AGS for Lucasarts-style), there's also RPG Maker. Haven't really used these myself, but they seem to be pretty straight-forward as well with an easy-to-learn language (at least I assume it uses a language, and seeing the amount of games made in it, and the range of people who can make games in it, I'd say it's easy to learn). RPG Maker's mostly for making console-style RPGs (kinda like Final Fantasy 6 and the likes)
If you're looking for something more advanced, you got the Wintermute Engine, which has a free version and a commercial version, and Visionaire, which has a free and a full version, it seems. These allow you to make adventure games in 3D, as well as cartoonish games. These require more graphical abilities, but the coding seems to be reasonable too. Haven't tried them out yet (found out 'bout them yesterday), but the coding seems to be made into a GUI, implemented in the objects.
Beside these, there're the professional ones. BlitzBasic, DarkBasic, Blender and the likes. BlitzBasic and DarkBasic're said to be fairly simple to use (don't know it myself), but there're only demo- and trialversions available, the full versions being fairly expensive for somebody who's not planning to sell games with it ($80 and up). They do allow any style of game whatsoever (of course, for a text adventure, you're better off learning C++ than spending money on those
)
Blender's a 3D modeling program that allows you to make games with, too. It's only for quite advanced people, but it's powerful and free.
Aside from these, there're still loads and loads of other gamemaking programs, like Game Maker (which I don't really recommend... might be good, but learning its language's not that simple, and it won't help you understand any other programming language whatsoever, so aside from Game Maker scripting, it'd be a wasted effort)