I doubt many young gamers know that Sierra once was the biggest and most respected producer of classic adventure games. They kept that status for quite a few years, until LucasArts took over with extraordinary original titles like Secret of Monkey Island. Hell, in a couple of years most of the new generation of gamers probably won't even know what a point-n-click adventure is!
But Sierra was the first to successfully introduce true adventure games. King's Quest 1: Quest for the Crown is, just like the first part of Police Quest, Space Quest and Leisure Suite Larry, a predecessor of the proper point-n-click games these series would become. These early games are hard to define; they are something between the ancient text adventure in which you only saw text (e.g. Zork) and the classic point-n-click adventure (like Monkey Island) - which has by now also almost become obsolete.
In the first Sierra adventures on the PC you still had to type commands, like in text adventures, but you now saw the actually animated character you were commanding. This meant the game still relied primarily on textual input as interface. Of course, since the Master System didn't have any sort of keyboard available, such control was impossible for Sega's 8-Bit pride. Instead, possible commands have been preprogrammed and it is possible for the player to select them in text menus. E.g. if you're standing for a walnut you can either select "pick up" or "look at" the "walnut" and so on. It works quite well - at least you don't have to figure out what to type all by yourself (but the menus are a bit disorderly). Objects which are useable in some way show up in the same list as the objects you already got in your inventory, which makes it easy to miss crucial parts.
The story behind the first King's Quest is the basic stuff early adventure were known for - the King sends your character on a quest to get the Magic Mirror, Magic Shield and Magic Chest of Gold'. I am not kidding, that really is the whole idea of your quest! The graphics are actually better than the original PC version, which was quite pixelated. (But the PC remake of the game surpasses the graphics found in this Master System port). The audio isn't particular interesting: there is a cheesy tune on the title screen, but apart from that there is almost no sound to be heard. Your actions are accompanied by minimal bleep-sounds, which will be familiar to anyone who ever played a prehistoric DOS game.
For present-day gamers the gameplay is very repetitive and tedious. Often you will find yourself aimlessly wandering around without a clue what to do, hoping to see some object which happens to be preprogrammed in the text menu. The most annoying part, however, is the numerous ways in which your character can die. It even starts on the first screen of the game: if you don't manage to pass the bridge on the exact pixels, you'll get the message "You're in the deadly water. There is no hope" and die. Water seems to be very deadly in the world of King's Quest, and it will accidentally happen you drop into it and pass away. Some screens have been connected to other screens which have water on the edges. So, when walking in a new area, it's possible to drop into the rapids and die without even suspecting any form of danger! It makes it even harder that sometimes you are supposed to swim, but there is no way of telling the water in that spot isn't the deadly kind! If you die, you have to start the game all over again, which is a tedious process. However, it is possible to save your game mid-ways by mean of some sort of 30-letter password system. It is quite long to write down, but it works accurately.
Although one can be very critical of King's Quest, I still found it a unique experience to play a rare type of game like this on the Master System. It just differs so much from other games on the console it's almost an oddity. I think it is the only "graphic adventure" available on Sega's 8-bitter, but don't expect the same quality as LucasArts' amazing Maniac Manson which was released on the Nintendo Entertainment System. Overall, a game like King's Quest is barely enjoyable by today's standards, but you may like to check it out for its curiosity or historic and nostalgic values.