Microsoft doesn’t require indie developers to be exclusive to the Xbox One console the way it does with the Xbox 360, but one of the company’s rules is causing some smaller developers to look elsewhere.

The Xbox One’s indie program, [email protected], insists that developers release games on the Xbox One on the same date as other platforms.

However, the company waited until July to change its rules regarding self-publishing on the Xbox One, at which point many indie studios had already signed up with PlayStation instead.

To remedy this, Microsoft added a loophole: games signed up to Xbox One before Gamescom in August were allowed to come out later on Xbox One, thus allowing indies more time to get to grips with the console.

This led to Dutch studio Vlambeer (Ridiculous Fishing, Serious Sam: The Random Encounter) to hastily sign its upcoming game Nuclear Throne to the PlayStation 4 before Gamescom in order to have more time to work on the Xbox One version.

Vlambeer co-founder Rami Ismail told Joystiq it wasn’t out of spite, just that his studio wanted the maximum possible time to port the game.

"We'd rather Microsoft allow us not only the freedom to self-publish, but also to publish in whatever order we prefer,” he said.

“We'll keep pushing for Microsoft to drop the clause, and we'd recommend any other developer to do the same."

Now Australian developer Witch Beam has revealed that its twin-stick shooter Assault Android Cactus will launch on PC at the end of January 2014 and on PlayStation 4, Vita, and Wii U shortly thereafter, but that it won't launch on Xbox One thanks to the launch parity clause.

"The simple answer is that our plans wouldn't meet the launch day parity requirement of the [email protected] program," co-creator Sanatana Mishra told Eurogamer.

"We started development on our other console versions long before self-publishing was an option for Xbox One and the only way we could meet that requirement would be to delay the other versions of Cactus.

"We also didn't have an exclusivity agreement in place with another console platform before the [email protected] program was announced, which could have allowed us to get a waiver."

That said, the ID program is very developer friendly and light years ahead of what Microsoft were doing even six months ago, said Mishra.

"But it's also coming in late with a clause that punishes those who have been developing on other platforms that were readily available for the past year, and that's something they need to fix before it's a viable option," he added.

This week Microsoft listed 32 indie studios that had signed on to its [email protected] program, including Double Fine, Iron Galaxy, Half-Brick, and Team 17.