I'm delighted to hear (from fellow Krypton Force fan Andrew Joseph) that another copy of "The Mask" has shown up on eBay after all this time!
Until now, the copy I own was to the best of my knowledge the only one ever released in the UK! Nobody else ever seems to have even heard of it, not even the BBFC listings! But hey, it looks like they made at least two of them. Maybe there were even more - in Australia, it seems a whole four volumes of Mission Promete came out, although it's almost impossible to find any trace...
See this classic blog post for full details of the wonders of Krypton Force, if you haven't already. You probably have, though - it's the single most visited page on this blog, according to the Blogger stats page! There's a whole army of Krypton Force lovers out there! And quite right too - those videos are wonderful!