Plazma Burst 2 might work in some web browsers, but it is also should be possible to run Plazma Burst 2 just like any other Flash game without web browser.
In this case you will need Flash Player projector and get it either from official website (link "1-optionA") or you can also download earlier unpublished version of projector at this page (link "1-optionB". Plazma Burst 2 might need earlier version in order to support Multiplayer mode that might not be available in most recent version of projector).
Once you have Flash Player projector - you'll need .swf version of Plazma Burst 2 which you can get from previous page or from here (link "2").
(then press "Download the Flash Player projector". Never download Flash Player from websites that you don't trust, also, you should not run .swf files of unknown origin either. In other words - trust .dmg and .swf files you download as much as you would trust any executable application)
1-optionB. Earlier version of Flash Player projector
(from https://web.archive.org, you could find Flash projector and download it same way here actually)
2. Plazma Burst 2 in single .swf file