What was but a rumor yesterday has today become a certainty: Stockholm, Sweden-based Bionic Commando and Terminator: Salvation developer GRIN has shut its doors.

Their website now contains little more than one final message from co-Founders Bo and Ulf Andersson, titled "The last Credits from the brothers GRIN."

"It is with a heavy heart we announce today that GRIN has been forced to close its doors," the message reads. "This as too many publishers have been delaying their payments, causing an unbearable cashflow situation."

We are presently unsure exactly what this means, whether it's a reference to the lower-than-expected sales of their games, or if publishers screwed them over and put the final nails in their coffin.

The site also reveals that they were working on one last unannounced game, one which they "weren't allowed to finish." And speculation begins right... now.

They give thanks to a number of groups and individuals, including Capcom USA, stating "Thanks for being honest, a rare gift." In response, Capcom posted via their Twitter: "gl to all the homies at GRIN."

However, amidst all the darkness, there remains some light; like a number of employees before them, some 25 ex-GRIN staff who were laid off in May have gone on to form a new studio under founder Peter Bjorklund called Outbreak Studios. Bjorklund's last work for GRIN was as Lead Programmer for the poorly-received adaptation of Terminator: Salvation.

"Outbreak Studios believes in having a small number of core employees that are extremely dedicated, focused and deliver high quality," the studio said on its official website. "Most of our associates have worked in the game industry for more than ten years. All of them have worked together for several years."

Develop says that the group's Twitter reports they are hard at work on their debut title. They have also pledged to develop for a number of platforms, including Xbox LIVE Arcade, the PlayStation Network, iPhone, Games for Windows Live, and PSP Go.

Another aim the group has is to "deliver online components for AAA titles, both existing or upcoming."

We wish the best of luck to those remaining GRIN employees affected by the closure, and hope they will soon be able to get back on their feet.