A bullet hell on NES that has a much better (and clever!) sprite flickering system compared to that Touhou demake: the rows with the biggest amount of sprites get focused, leaving the other ones mostly intact. This is pretty useful to see what's closer to you without many issues.
There are some cases where the traditional "everything flicks" can help, and you can set that up too if you want.

Other than that, it kind of plays like a speedy CAVE game, with a lot of aimed patterns and focus on pointblanking.