"Asset Flipping" is a term that refers to the practice of building a game almost entirely out of pre-made assets with little original work. They are more commonly found on Steam.
Valve Corporation refers to asset flips as "Fake Games"
Origin of name
The term was coined by YouTube personality Jim Sterling, who likened it to the practice of house flipping.
The process of game development has been drastically facilitated with the introduction of easy-to-use engines like Unity that anyone can use. Some of these engines have stores were developers can purchase pre-made assets to use in their games. The core idea behind pre-made assets is to save costs and time in details that developers may not be experienced in; the assets can be studied to learn how they work, be edited to match the art style of the game in question, be used as placeholders, etc. They can also be great help for developers who aren't very good with art design. The engine stores also offer "starter kits", fully functional alpha-builds with little content that developers can as frameworks to start working on an original game.
There's nothing wrong with using pre-made assets, as long as developers make their own original work with those assets and adjust them to match the game they're developing. Unfortunately, it is also possible to make a game out of nothing but pre-made assets. doing so is as easy as purchasing the assets and tossing them into the game engine with some basic coding. As a matter of fact, pre-made asset piracy is notoriously easy so there's no guarantee that asset flippers are paying for them.
Pre-made assets usually only have very basic coding and AI because developers are supposed to use them as a helping tool, not make the whole game with them. Games built like this tend to be barely functional, full of glitches, lack content, are short in length, have basic enemy AI, lack any art consistency, and overall are just bad games due to having little original work. Because asset flipping takes so little effort and time, it is easy to quickly produce large amounts of shovelware this way. Sometimes asset flipping is as simple as buying a starter kit alpha-build and changing its title without doing ANY work whatsoever.
This practice is heavily frowned upon because it results in low quality games, and is considered very lazy since developing a high quality game takes months to years of hard work. Steam Greenlight Quality Control system makes it far too easy for anyone to put a game for sale on Steam, because of this people can put quickly made asset flips on the store to make a quick buck. Genuine game developers also tend to get angered at asset flips because they can cost just as much as the games those real developers made.
The main method asset flips make a profit is via Steam trading cards. By selling the game for dirt cheap, the users can sell the trading cards and make their money back, then the developer gets a cut of the profit from the cards. People can abuse this loophole by producing tons of asset flips and putting trading cards in all of them. Some even rely on using bot users to farm the cards en masse.
In recent years, the amount of "game developers" and outright scammers that use asset flipping to spam games into Greenlight has increased drastically. a particularly infamous example being Digital Homicide. As a result, Steam has become clogged with massive amounts of shovelware that overshadow real games, and because asset flip games tend to be really bad quality, the practice has also made authentic indie developers look bad.
Valve's fight against Asset Flips
One of the more controversial aspects of Asset Flips is that Valve appears to simply allows Asset Flips to keep spamming Steam with little trouble. It is also known that Valve gets a cut of the profit Asset Flippers generate so it was suspected this is why they didn't do anything to stop it.
On April 2017, Jim Sterling and Totalbiscuit had a meeting with Valve about Steam's future. During this meeting, Valve admitted that asset flips are a problem that they want to get rid of, and that indeed Trading Card farming is how asset flips make a profit. Valve suggested new policies that in theory will make asset flips completely unprofitable, that way shovelware developers will be less encouraged to continue spamming them..
In late May 2017 Valve announced a new policy in which games aren't allowed to get Trading Cards until their algorithms determine that they aren't Fake Games. Without Trading Cards, Asset Flips would in theory completely stop being profitable. This announcement was met with skepticism because their algorithm can potentially fail to work or Asset Flipper will figure out a way around it.