It's often said that the opening 30 minutes of any video game are possibly the most important. Not only do they give the player an indication of the title's quality, but they can also be used to show how the game works, establish its core mechanics and tease elements of an epic storyline.

With this in mind, game developer Stephen Mortimer has started a new YouTube channel devoted to the first 30 minutes of a series of titles he has never played before. He plays the opening half hour and then - from a game design perspective - feeds back on what worked and what didn't.

Why should you care what Mortimer has to say? Well, he used to work at Nintendo Software Technology and contributed to titles such as Mario vs. Donkey Kong 2, Mario vs. Donkey Kong: Tipping Stars and Mini Mario and Friends: amiibo Challenge.

After 11 years at NST he has now moved on to Riot Games, and plans to run the channel in his spare time. First 30 of Game Design is well worth a look if you're in any way interested in how games are made, and Nintendo fans should be interested to know that Mortimer has already covered Paper Mario Color Splash and Rive. Have a watch and let us know what you think.