Hey there cool entry I really like the dragons vs demons things it's cool and pretty unusual for a SHMUP so kudos on that.
This game has a pretty interesting take on the SHMUP gameplay formula too where you cant actually die and your score is just based on how many guys you let past. Sadly it looks like the counters for dragons defeated/escaped aren't functional but I think it's a cool idea that could be built on a little more. In the game you have different enemies each with their own flight pattern which is a good start but beating them is all the same strategy, you just follow them and shoot. You might consider enemies that shoot at you but they don't kill you just stun you or something like that. That way you keep the game accessible and there's no losing but also have a little more variety in the challenges presented to the player. The shooting is kind of bothersome, I would suggest making it so the player can just hold down the spacebar instead of having to spam it to shoot.
As far as design and use of the limitations you only had one upgrade which wasn't the theme but I do like the upgrade. You level up as you beat more enemies and then turn into a big more powerful dragon. This is cool I would've had it so that you fill up your xp and then get to choose when you turn into the big dragon instead of it being automatic. That way the player has a little more agency and the upgrade doesn't get wasted when there are like no enemies or something like that.
The visuals are good I like the cute dragon sprite and his cool upgraded version and all the demons have intriguing designs. There's just like no feedback when things happen no particle effects or shake or anything. And then there's also just no sound so that's that.
Really unique project that has some interesting takes on previously established SHMUP mechanics it just feels incomplete in it's current state. Thanks for creating and sharing!