Snap’s latest generation of augmented reality Spectacles have been lambasted by one of the engineers who helped to create them. The glasses, revealed earlier this week, were described as “a disaster” by Sterling Crispin, a former design engineer for Snap.

“I worked on these for about a year at Snap, and I have a million negative things to say about the experience and the device, but I think the product speaks for itself and is obviously bad,” Crispin said on X in response to the new Spectacles being unveiled. “I hate these things.”

“This individual departed Snap before key hardware and software design decisions for this version of Spectacles had been made,” said Snap spokesperson Cassie Bumgarner in response to an inquiry by The Verge.

While Crispin noted that AR and VR devices all face conflicting limitations around things like size, weight, performance, battery life, and production scale, he criticized the balance of features offered by Snap’s new Spectacles — but didn’t scrutinize any specific elements of the gadget. “This device is a set of very bad decisions that compounded, making them even worse,” Crispin said. “Everyone working on it knew the problems and who was making them.”

For its part, Snap doesn’t seem to be saying these glasses are ready for mass adoption by any stretch. The new Spectacles aren’t being sold to the public and are instead being made available to a limited number of Snapchat AR developers. Snap CEO Evan Spiegel told The Verge that he doesn’t expect AR glasses to be a meaningful business until the end of this decade.

But they’re still expensive glasses, and the product is meant as a showcase to get developers excited about AR and Snap’s platform for it. Developers have to pay $99 per month to rent them, with a minimum term of at least one year. Meanwhile, people online across Reddit and X have been poking fun at the device’s limited 45-minute battery life and 46-degree field of view (up from 30 minutes and 26.3 degrees on the previous model.)

In his hands-on with the glasses, my colleague Alex Heath said that the hardware has improved for Snap’s fifth-generation Spectacles, but the software “still feels pretty basic for a standalone device.” He said the field of view fell far short of feeling like a regular pair of glasses and made “augmented reality considerably less engaging than the real world.”

Update, September 20th: Added comment from a Snap spokesperson.