The Longhorn ad and Gemcraft Chapter 0 don't play well together with Firefox. (59.0.3 (64-bit)) on Windows 10. Longhorn ad spins for awhile - never plays. Click it and you are taken to the Longhorn web page. Close that page and the PLAY button is on the GC Chapt 0 page, but clicking does nothing any more. Refresh and start over. There appears to be no way to get to the game.
Yes, the video ad that appears before the game. The screen capture is simply the little spinning circle effect (with the lines chasing each other around) in the black screen that shows before the game PLAY button appears. Let me see if i can grab it here... Nope. The Longhorn ad is no longer showing. I got a Staples ad, so it is going to let me play! This is the second time i've run into the problem - i think i had it Sunday, too.