I somehow make it further and now I have 207 HP, Dash lv1, bullet lv1, resistance lv1 and diving, yet I still can’t seem to pass the other 2 paths in electric city. And I feel that I can’t deal enough damage to proceed east from the first save point in deep water. The shell thing is quite tough (it only becomes vulnerable for a short window), and after dealing with it and proceeding to the next room, I don’t have enough light to deal with the turtle thing, and these two rooms only offer clear path after enemies are all gone...
This game is indeed quite challenging and feels quite non-linear, but I’m not sure I can finish it...