Worlds of Power

Worlds of Power was a series of novelizations of Nintendo Entertainment System games published in the early 1990s by Scholastic Books. They were written by several authors using the pen name "F.X. Nine". The books averaged about 120 pages long, and featured strategies for the featured game as an added incentive, either in a trading card on the inside cover or at the end of each chapter. At the end of each book was a list of recommendations for other books the author "thought you might like". The quality of the books varies, as does the faithfulness to the game's plot.

There were eight books in the series, each named after the game on which it was based:

There was also a "Junior Worlds of Power" series, aimed at an even younger demographic. They were physically bigger, but only about 70 pages long. There were only two books in the series: Mega Man II and Bases Loaded II.

Tropes used in Worlds of Power include:

Adaptation Expansion - Considering how simple the games' plots were, a lot had to be added, and many of the stories added a great deal of backstory, or even additional characters. The most notable here is probably Blaster Master, which adds Eva, a human from another planet, as the original owner of the Sophia III vehicle.
Ascended Fanon - The Blaster Master adaptation is canon. Crazy, isn't it? Specifically, in the backstory of one of the later Blaster Master games, Jason is said to have married Eve, the woman from another planet who appears only in the book and is his companion for much of the story.
Deus Ex Machina - Occasionally. In Bionic Commando, the arm has several other highly convenient functions that come in handy at the last second.
Did Not Do the Research - We're given definitions for "gaiden" and "shinobi" in the Ninja Gaiden book that the author obviously made up.
Improbable Age - Ryu Hayabusa of Ninja Gaiden has his age lowered from adulthood to 13, making his travel to America and his whole journey rather improbable.
In Name Only - Before Shadowgate has nothing to do with Shadowgate. It's ostensibly a prequel.
Lighter and Softer - Yes, they've been bowdlerized from E and E10-equivalent games. Wildlife is non-fatally diverted away in Ninja Gaiden--or turn out to be robots for no real reason. Nathan "Radd" Spencer, or the guy posing as him anyway, takes out Badd troops with karate and tranquilizers (though he still explodes Master D at the end).
Revised Ending - In Ninja Gaiden, Ryu's dad doesn't die in the book like he did in the game.
Tagalong Kid - Many of the books, though not all, have the main character actually be some middle school student who goes on an adventure with the hero.
Totally Radical - Used in a number of these books.
- This is actually used as a weapon against Dracula, of all people.
Trapped In Video Game Land: Happens in the Castlevania book, in which the Kid Hero gets transported to the world of the video game itself (which is treated as specifically the world of a video game, unlike, say, the Wizard and Warriors book, which treats Kuros's homeland as a fantasy world or other time period).