I can give you guys a bit of feedback.
Movement:
The movement felt good. I would add a jump input buffer (you can hit jump before touching the ground to jump anyways) and a coyote jump ( you can still jump in a small time window after falling from a platform). Also a variable jump hight would be nice.
After you get the double jump, the wing effect always plays, even when not double jumping.
I like that you can use the morph ball at any time, not only on the ground. In most games that have some mechanic like this it's limited to be used grounded (even in my own metroidvania) but I think it works here and gives you a nice feeling of fluid movement. If you wanted to improve on it you could try giving the player more speed when inside the morph ball.
Crafting:
I think that this is THE feature of the game. Even tho you did't get the balance right. If you manage to implement the save system and make the grind take less time I think it could work really well.
Some ideas I have would be to give every enemy a pool of items to choose from and make the crafting require more recources. Then make a scanner or something that tells you what stuff enemies drop. And probablly the best thing you could do is to make bosses drop unique items so you can limit progression.
Visuals and sound:
The style is very nice. It reminds me of environmental station alpha but less busy. I would make different angles for the gun to point at tho because rotating pixels this large is just not pretty. The Backgrounds and colors were really good.
The Music and sound are also quite good. I think the music fits perfectly and never gets annoying.
Combat:
This is the area were I have the most problems.
Almost every enemy needs either more or even SOME telegraph to their attacks.
The bats can stay inside you and deal damage and it is very annoying to kill them because you cannot hit them when they are on top of you. You could make them explode when they touch you, give the player knockback or change the behavior of the bats.
Fighting enemies in one tile tunnels is not fun. Try to avoid it ,make the bombs do more damage or make them able to be thrown.
Some indicator of how much hp an enemie (boss) has left would be nice. The better way to do this is of couse to make different sprites for how damaged they are but an hp bar would do the job just fine. Or do the metroid thing were they get tinted red when their health gets lower.
Currently you can spam bullets. Implement a delay so you cannot use an auto clicker to turn the game into a joke.
I hope this is useful.
I look forward to playing the game when it's done.