Yesterday Dark Horse celebrated the announcement of Mass Effect: Invasion, the third of its Mass Effect digital comics, by offering its earlier Mass Effect digital comics - Redemption and Evolution - free of charge.

Unfortunately, so strong was demand for the free comics that the Dark Horse servers buckled under the strain and prevented many fans from grabbing the free downloads. Sadly, Dark Horse won't be extending the offer, but is "sorry for those who experienced difficulties".

"We're proud of our digital program and are committed to being the best in the business," said Dark Horse. "Even now our technical-support team are taking additional measures to ensure that we're improving our server capacity and are able to fulfil all requests."

The firm added: "We've got big digital-comics events planned for Mass Effect in the future and we're working hard to make sure everyone will have a great experience."

On Twitter Dark Horse added: "Look forward to future Mass Effect promos."

Mass Effect: Invasion will launch in October, ahead of the March 6 release of Mass Effect 3 on Xbox 360, PS3 and PC.