An awesome "byte-sized metroidvania"!, could beat it (on normal) in ~30 minutes. The presentation was great, and it managed to be long enough while keeping its small scale, at least longer than what I expected at first.
Some of the platforming bits were a bit tricky, but nothing ridiculously hard to make it seem cheap, and it was fun to end with a boss fight AND an escape sequence. It really seems like you took the most essential elements of the "metroid-vania" genre and made as much as possible within the Ludum Dare limitations.
Makes me wonder If you could keep making more "mini-worlds" like this in a sequence, just a thought.
Good work!