Oh yeah, the flash works fine. Has a little test button on its hotshoe attachment and everything. It's more adjustable than the flashes I have for my Nikon FG and Zenit EM. Head tilts up and side to side easily and it screws onto the Holga 120N tripod mount fine and since it's a very simple hotshoe attachment, the Holga doesn't have problems with it either. The flash head has a diffuser that pulls out to diffuse even more and it has a chart on it for film speed, aperture and distance in ft/m. I didn't notice any over exposed/washed out photos in my first roll of film out of it but I'm pretty wary of keeping at least 3ft away from anything when I'm working with a flash. Very nice recycle time of 10seconds too!
I'm beginning to think these things are quite neat, although not quite their sometimes asking price of 30GBP/$60. I don't think we did too badly paying 8GBP for it considering holgas cost 19GBP usually here.
I also like that it takes 4 AA batteries (two for the motordrive camera and two for the flash) as my much more modern point and shoot 35mm camera uses an annoyingly expensive lithium battery.