Thanks for playing!
With the slow movement, I'm not sure if it's "slow", or points of interest are "too far apart", or that there's not enough interesting stuff during the travel. It definitely feels like a slog at points though. (^^;)
I'm glad the secret health upgrades turned out well, I really scrambled to put them in at the end. (≧ v ≦)
I think it very literally is just the player moves too slow. There's not a lot you can do to spruce up the level design when the player only moves a few tiles a second, and the distribution of points of interest felt perfectly fine to me in most cases. Adjusting the player speed is also just a really easy thing to do so I wouldn't be afraid of playing around with it and seeing if it feels better at a faster speed. It doesn't need to be drastically faster, just a moderate increase can really change the effect it has.
