Hey all! My shmup Cyber Seraph is releasing on 17.07, so that's very soon. The game will have 15 achievements for all 15 bosses. More bosses will be released in the future including some non-boss missions.
Right now you can get the free demo from the store's pages for free. It has 3 bosses (2 story bosses and 1 bonus boss), and 3 achievements, so be sure to hunt for them! =)
Take care!