Pretty graphics, but lacking otherwise
This is in essence repetitive grinder game with pretty graphics.
The enemies have some variety, but they only come in only 1 way - in a vertical line. You fight this line of enemy over and over and again, and it becomes repetitive very soon.
The inventory management is a hassle. As it previously stated, separate tabs for weapons and shields will be very helpful.
Finally, a few things are needed. Enemies need to come in a variety of ways, not just in a boring vertical line. Streamlined inventory with separate tabs. More interesting boss fights that consists of more than shooting at the boss until it explodes. And maybe a shop where you can sell/purchase new gears?