So amazing

I would word it a bit differently and make it more "samurai-y", but the basics are there.

rather literally: Flash content (direct object marker) display method (particle) doing(but), flash plugin installed wasn't.

I would probably do something like フラッシュ内容のものを観てみるが、フラッシュがインストールされていません。

and play with it to sound more old-timey and samurai-i (which I failed to do just now so you only get the above). I am not a native speaker and, arguably, not even a good one, so take that for whatever it's worth.

Edit: I actually was trying to find out why 'Flash' was actually called that and can't find an authoritative answer. I wanted to do some creative lyrical stuff which with words to use as flash (電光石火 for example is flash as in 'like a flash', but there's 閃く which is a normal verb meaning to flash in the visual (non-perverse) sense).