Thanks for the feedback man! There's no such thing as too harsh criticism

we are at the end of our early access now (me and my buddy, we are doing this together as a hobby) and we are getting a lot of support and criticism of all forms, and everything helps - we are trying to take everything on board.
You're totally right - we don't have that much experience in danmaku or shmups in general. We come from a more RPG-oriented background. (When I say RPG, I mean specifically that element of RPGs that focusses on steady and open character skill progression, not the plot etc). This game is almost like a RPG in shmup clothing. (That also explains the health thing, etc - Cosmonator is very unlike a danmaku in that sense: you're supposed to take hits, even unavoidable ones sometimes; this might inspire a player to buy defensive upgrades or defensive spells, just like you would in an RPG - the 'depth' of the game, i.e. of all the different upgrades, including armor, shield, drone repair, etc, and all the defensive spells come into play there). All of that might really not sit well with shmup purists. I get a feeling that anyone who's really into one-hit-death danmakus is probably not going to enjoy Cosmonator; in the same way that people who like RPGs might not like fast-paced arcade games. We tried to create a balance; perhaps while trying to keep both sides happy, we are at risk of alienating everyone:/
All of which doesn't mean we can't learn more from shmups and danmakus though - I'm gonna look into that a bit more, it's good that you mentioned that. It might indeed be down to bad level and enemy design, as you say, in terms of what a good shmup should be - how it should be designed.
But also I think (or I'd like to think!) a big part of the problem is that the real interesting challenge of the game only comes out in the later episodes: because the game is structured like an RPG in terms of its character progression (start really weak and slowly build up your character), the first 10 or so levels really serve as an introduction, so as not to be too overwhelming while players get used to the dynamics of the game. Which means on most difficulties it will be pretty easy, boring even, just like in an RPG when you set out; and on impossible the only times when it will really be challenging is likely to be slightly frustrating, as you say. Later on that changes - you will find even on normal mode, there is often a LOT of stuff on screen - and also the different enemies and attack patterns become more interesting.
All of which obviously means that having a demo with only the first few levels doesn't really do us that much good!

(better than nothing i guess? I've considered making a different demo, with only one level, but later on, and you're already kinda powered up, so you can get a feel of what the real action feels like) ...and I obviously won't expect you to buy the full game if you didn't really get into it - but it's a shame because I'd really like to know if you will still experience those issues that you mention, later on in the game. BUT the fact is that you are experiencing them at all - probably you would have put the game down by now even if you had bought it, being demotivated? - that's a concern anyway, obviously. I think unfortunately for us many traditional shmup players will feel the same way. It's weird but really we designed the game more with RPG players in mind, and we didn't really think about market or success etc when making it, and we totally didn't do a lot of shmup or danmaku research, as you suggest - I have to be honest. We just winged it. So all of that is a bit all over the place.
On the bright side, we are also getting some really good feedback on steam, presumably though from people who are not that familiar with the danmaku genre

I guess we'll have to be careful exactly how we market and to whom!
but yea man thanks for trying it and thanks for the feedback either way!