It was BlackBerry Friday.

Research in Motion, the maker of BlackBerry, continued its downward spiral yesterday with its shares falling more than 20 percent to close at $27.75. Analysts also piled on with a series of downgrades.

RIM co-CEOs Jim Balsillie and Mike Lazaridis face criticism for not moving quickly enough to keep pace with the rapidly shifting mobile marketplace. As a result, the once-dominant BlackBerry is eating the dust of Apple’s iPhone and Google’s Android mobile software.

“The deterioration of the stock has been stunning and alarming,” said analyst Charles Wolf with Needham & Co. “It’s going to take something very dramatic to turn this around.”

Late Thursday, RIM announced looming layoffs and earnings guidance that fell short of expectations, prompting an after-hours sell-off in its shares, which sank 15 percent.

Analysts and investors are skeptical RIM can rebound after a series of missteps developing a new platform and next-generation products, which are facing months of delays.