Visuals:
1 ... maybe adding flickering stars based on different values -> that would be perfect
2 ... make spaceship colorful
3 ... otherwise main menu looks tunned well
4 ... flying plants/rocks (is this intentional?)
5 ... I have feeling of possibility planets feels empty (low number of object, a lot of empty space where is not expected to be)
6 ... focus on cosmos animations -> to enchant space look
6.1 . wind/dust particles flying over words
7 ... I do not want to read missing quest -> what to do?
7.1 . maybe some nice GUI animation color flicker with little shake to gain eye focus
7.2 . or some future Avatar tablet design
8 ... some planets feels rushed (detail between planets doent align
9 ... water is complex (usually you would require to have shader & been able to step into -> currently it looks little of like ice, kinda)
Controls Walking on planet
1 ... very good, is possible to add running?
2 ... auto jump 2nd, 3rd time after jump is successful without releasing & pressing space button
Design
1 ... show location of spaceship (me getting lost + it fits your story)
2 ... There are small chances of getting lost
2.1 . maybe give player bot to help you discover world
2.2 . trackable pads to mark where have you been
3 ... I love this small planets design
Sound
1 ... very good no pattern found & its intriguing with exploration (Hellion)
2 ... some sounds might look misplaced (Hellion vs "Earth")
Bugs:
1 ... I am able to walk into rock, over some plants
Good idea, I would mostly focus on presentation of mystery & cosmos