Unfortunately, it seems that the 'blocks' and Astro immediately disappear when I click to drag them. The first one I click appears to drag for a tenth for a second before vanishing. But if I refresh the page while explicitly already in fullscreen, I'm able to drag the first cube into position, at least, before the issue returns for every subsequent block. Restarting the level with the button also helps for a bit, but in any case I can't complete the first level without *something* disappearing. Whatever the problem is, it didn't log to console.