Overall, interesting gameplay loop. A few notes about my experience.
1) I was having a weird sound bug when I released a movement key; almost like the sound speed up to end it at that moment or something? It mad a very loud putter like sound.
2) Great UI start! The only grip would be implementation of a map or something, to know where you have gone or not. I am alright in maze like situations, but I know a few of my friends who would like this who can get lost in a hallway in a game. You could theme it as a sonar map, which would give that sonar sound more reason to be there.
3) Probably put the 'first' fragement closer to the note about it? I didn't realize how to use the items (as in they are automatically used if they touch the thing); and that slowed down my gameplay as I skipped multiple fragements not know what they were or how to collect them.
Was pretty fun when I found out how to play properly though!