Why videogames based on established properties almost always seem to suck? Here's why:
They are just productsLicensed videogames are often just part of The Merch, they are just like the toys, the clothes, the cereal, the coffee mugs, the bed sheets, the shampoo, and so forth, they are meant to be bought, not to be played.
How to avoid this:Treating the licensed game with respect, with the same care that the source material receives.
How to avoid this:Give the developers a better time schedule to finish the game, that's why games based on movies that are years old when the game came out are usually better, another great option is making a game that has little to do with the movie or better yet, making a licensed game of the franchise but not directly based on an already told story, instead having a original story.
They sell just because of the nameThese games are meant for fans of the source material, since they are going to get these games no matter if they're good or not, quality is just optional, this is even worse with games for kids.
How to avoid this:Once again, treat the game with more respect and know that quality is a factor that helps boost sales. many different and discordant gameplay genres are added to the mix due to the variety of the source material. The worst cases are game adaptations of properties that have little potential for a videogame, like psychological dramas or sitcoms with no action or tangible conflict during most of the plot. Typically, their gameplay is very linear and involves the player being forced to do a lot of artificially hard mundane everyday tasks occasionally interrupted by a cutscene.
How to avoid this:When making a licensed game, choosing a franchise that can be turned into a videogame with ease, like it's said right above. If you absolutely have to adapt a "Slice of Life" - type plot, making the game have a original story instead of adapting a story that was told in the source material may help. If the source material has nothing that can be made into a game, then you shouldn't even try.
Trying to mimic a popular game genre to sell more copiesWhen making a licensed game, choose a genre that fits very well with the source material. If it's a action movie, make an action game, if it's a musical, make a rhythm game, if it's a mystery book, make it an adventure game, if it's a racing movie, make it a racing game. There are many instances where the executives choose to make the game in an unsuitable genre similar to the more successful games around (this especially happens with licensed games for kids).
How to avoid this:Choose the genre better suited for the source material.
People that made the source material aren't consultedEven though videogames are a medium unlike any other, that doesn't mean that people that made the source material so good and successful aren't necessary for the videogame adaptation. They can help with the plot, the writing, the jokes, the new characters, the puzzles. If they resist the temptation to turn the videogame into a film (see point 4), they can ensure that the adaptation stays true in spirit to the original work.
How to avoid this:Obviously, having input of the original staff on the game adaptation.