The color palette changing in each different area was a nice touch and lent it some visual variety despite the 1-bit limitation. It also had an interesting appeal in its simple design similar to the first Zelda game. Since nothing was explicitly spelled out, finding the ending became an intriguing mystery, even if the narrative surrounding it was fairly simple.
I do feel that the recharge time for attacks/dodging was a bit too long, but the length of time did help give the bullet dodging elements time to shine, so I feel they would only need a slight reduction in charge time rather than anything drastic. Overall, it was nice to go through!