I tried this again.
Couple things you could improve (major things):
Take the time to write something in the description, specially when no sort of tutorial is in the game and there is not a clear objective.

Took me a while to figure that I had to press space to do some sort of "interaction" with the objects (collect the balls).

Is there anything else to do that I'm missing? I collected couple balls, got into the platform in the sky, went over the moving platform and climbed something (also: it took me 3 attemtps to figure that was some sort of ladder - next time I'd suggest to create it as an actual ladder, a vertical cube is not a ladder in a normal player view). Then I jumped down and took 1 or 2 more balls before quitting. Let me know if I had something else to do or if this is the game! (which would be totally fine!)

Now couple things you could improve that I found off FOR ME! (might only be me, so take this with a grain of salt!):

1. Lighting was odd. I had to put that in fullscreen (even if it doesn't go fullscreen) to be able to see a bit better the game, as it's too dark.
2. The fact that the cursor is left unlocked makes it hard to turn around, as eventually the mouse will go beyond the game window, and reach the screen limit. Avoid this by setting the cursor as locked (and maybe invisible too).

But at least is playable this time!