@Mackpack, please note this forum is intended for reviews of the plugin (not the app, itself). The plugin does perform its currently stated function - hiding posts of a specific category from the home page of your blog. Additional features may soon be on the way.
Indeed, the app is quite similar to Instagram; yet, it allows you to retain rights to your images and has proven to increase traffic to your blog. Additional filters and editing options are coming in v2.0.
As you mentioned, most support is being handled at help.pressgr.am, and as the community grows, i'm certain support with improve. I've been using Pressgram pretty regularly and have begun some development on the WordPress end. Let me know if I can assist with any questions you might have.