The old version of the game uses Adobe Flash. It was announced that Adobe has ceased development on the Flash browser plug-in and will soon retire it. If the game remained Flash, then the site would soon cease to work at all. In addition, people dislike Flash. Other websites and search engines are reluctant to link to Flash sites, which has been preventing Just Jigsaw Puzzles from growing for years.
The new game actually has more options when it comes to total picture size and piece size. It also uses more of your browser window as play area. If you think the pieces are too large or small, try adjusting the options before starting a game to find a size you like.
Since the math behind carving the pieces needed to change with the new medium, the curves of the pieces are different. I don't believe they are any better or worse, but just different. If you have been used to the old shapes, I ask that you take the time to adjust to the new ones.
Lots of good stuff. The puzzle images are much higher resolution. While the original images looked fine on circa-2003 small computer screens, the new images are much better suited for today's larger high resolution displays. But the pictures themselves are the same. Also, more backgrounds, edge types and arrangement options. Also, since the game doesn't require Flash anymore, millions more people will be able to play it as many used computers and browsers that discouraged or outright prohibited using Flash at all.
Older browsers do not handle HTML5 well. On Windows, you should be using Internet Explorer 7 or better, but IE 10 or the Edge browser are best. On Mac, Safari works best. Firefox runs HTML5 games rather poorly, so you may want to avoid that. Chrome is fine. Older computers may struggle. I look at the statistics for the site and about 2% of all visitors use older (10+ years) computers. While I would love for everyone to be able to play the game, it is hard for me to justify removing features and quality from the game to support those older computers.
I am leaving the old version around for the time being, but will eventually have to remove it before Flash is retired. I'd like to remove it sooner, since as long as search engines see the sites as having Flash content, they will not rank it well. That means fewer new people will discover the site, which could jeopardize it's future. In the meantime, you can use the link in the left sidebar to switch to the Flash version.
After reading the above, if you like you can send me an email with any questions or suggestions. Thanks. -- Gary