Dinging it over game performance now seems an unfair argument to make since there's like what 2 prototypes and it's still sort of early-middle of life into development. They even stated in the video that the performance hasn't been finished or optimized so they have problems. I'm no seedi backer, but I get grumbly and annoyed anytime someone tries to show something off early to let people know, warn them it's not finished so things are beta, and then people call them out over stuff not working right. Well duh, you got told that much. Let them get their OS/firmware/drivers whatever it is finished, then slap them silly if it still struggles.
My only real gripe with them is not working out something so everything just works out of the box, even if it means reverse engineering the firmware and doing it yourself. 20 years ago a frenchman did it for PCE, then PCE CD and PCE Express and Arcade card drivers for PCE/TG16 under the named of Magic Engine. It's doable, been doable for decades now.
Is it unfair to judge the prototype on performance? Probably. But isn't it running emulation software and a frontend that is available (and working) for a bunch of other devices, like PC's, Raspberry Pi, etc? Do those devices struggle running those games? Also, if you were releasing your actual prototype to get reviewed, wouldn't you make sure that one of the best features that would get people to invest in your product works before sending it off?
Side note: I remember running real Sega CD games on an emulator (maybe Kega Fusion?) on a Dell tower PC about 15 years ago. I didn't have a Sega CD at the time, and I borrowed the games from a friend to see if they would work. The games ran great right off the CD-ROM drive. I couldn't believe it! I didn't have any Turbo CD games to test with anything back then, but I bet Hu-Go would've run them without issue. The Wii plays Sega CD and Turbo CD files very well, but can't read the discs unfortunately (something to do with the drive not being able to read CD's).