Welcome to the Rumour mill, VideoGamer.com's run-down of the big rumours currently doing the rounds in the video game industry. Every week we'll hunt down the juiciest stories and give our opinion on how legit they are. So, whether you want the ridiculous or the plausible, read on.

BioShock not coming to PS3

The Rumour: Contrary to popular belief, 2K Games' BioShock or its in-development sequel are not coming to the PlayStation 3. They will remain Xbox 360 and PC exclusive. This is due to Microsoft paying for exclusive rights and the extra effort required of a PS3 port.

Verdict: This one comes from rumour blogging legend Surfer Girl and goes directly against the Rumour from EGM that claimed the original game was heading to the PS3.

"BioShock is still not coming to PS3 nor is there plans for a PS3 version of its sequel," reads the blog.

Given BioShock's huge success on the Xbox 360 it's perfectly reasonable to expect Microsoft to want it to remain a platform exclusive. With so little known about the sequel, though, it's a little early to be saying it's a guaranteed exclusive.

Plausibility rating: 3/5

Online multiplayer in God of War 3

The Rumour Despite the fact that God of War has always been a solo experience, multiplayer is being included in the series' debut on PS3.

Verdict: This rumour stems from a job ad on the Sony Computer Entertainment America jobs page. According to the ad, Sony is looking for an "online gameplay programmer" to "join the team behind the critically acclaimed AAA titles God of War and God of War II." It sounds pretty conclusive, but elsewhere on the page our hopes of online co-op or similar are potentially dashed.

The bottom of the job ad reads: "Please be advised that the following job description may not reflect a position that is currently available. This job description may exist to simply gather interest, and may or may not ever become an approved open position. Thank you for your interest in SCEA."

A quick look at the other jobs listed reveals that this paragraph is also present on the listing for a number of jobs at Sony's Santa Monica studio. So, it's not out of the question, but far from confirmed.

Plausibility rating: 3/5

GTA 4 the most expensive game ever

Rumour: Rockstar producer Leslie Benzies has stated that over a thousand people worked on the GTA 4, and reckons that the game cost roughly $100 million, making it the most expensive game to date.

Verdict: There are a few things to consider here. Firstly, the current Guinness World Record holder for Most Expensive Game Production is SEGA's Dreamcast classic Shenmue at $70 million. So that's one issue sorted out. The bigger question is if GTA 4 did indeed cost $100 million? Given the size of the game and amount of content (lines of dialogue alone dwarf most other games) we wouldn't be surprised, but at the moment we're still just going on a guess.

Plausibility rating: 4/5