Atari has taken RollerCoaster Tycoon 3 off of Steam after developer Frontier Developments filed a lawsuit over unpaid royalties from the game. TMZ broke the lawsuit news last week, including a basic overview of the suit.
Frontier Development claims it's been working with Atari since 2003 when it struck a deal to develop the game RollerCoaster Tycoon 3 and a bunch of others. When Atari went bankrupt in 2013, Frontier says they stuck it out and amended their contract.
Atari's out of the red now. In April, Frontier started to believe it was getting ripped off, claiming another website showed higher sales figures.
Frontier says the site calculated Frontier should've received $3.37 million in royalties from Atari when they only got $1.17 mill. According to Frontier, Atari then delayed when it was asked for an audit of their sales report.
Since news of the suit broke, Atari has pulled the game from Steam without much explanation, while you can still find the game page for RollerCoaster Tycoon 3, the ability to buy the game on Steam has been removed.
While it makes sense for Atari to pull sales of the game, usually games get de-listed from Steam due to pending lawsuits. It is possible the page still exists because Atari expects to be able to return to selling the game relatively quickly.