I see on the game page that you chose the tag ‘Non violent’; not sure this fits well with the ‘Kill’ in the title! ;))

Some on-the-fly comments:

1. You can move a grey sphere while in the menu; it is expected?
2. Controls are QWERTY-only instead of layout-independent (although the game page also states ZQSD! Weird; my AZERTY does not agree).
   The arrow keys do work, but Left and Right are for turning instead of strafing, which is both classic and less practical in my opinion.
3. The map/terrain is pretty and detailed (as an example: a small mushroom behind a rock).
4. No sound? It helps give life and feedback for the player.
5. Clicking does not seem to shoot… Is shooting enabled only once you have found the three balls?
6. Is the double blue and red sign near a small bridge an implicit clue as to where the balls are? If yes, brilliant idea! If not… I suggest it. ;)
7. Where is the third ball?! I found two rather quickly, but I have no idea where the third one is! I have even searched below the two long bridges, to no avail…
   Unfortunately, I still don’t find it. This reminds me of some long hours spent scrutinising for secrets in The Witness! XD
8. As for the clone, found him by chance right at the start in a recess, but as I said, I cannot shoot.
   Found him again: semi-bug, his head is in the foliage! Although this may be legitimate, after all. :)
   

Stopping the test as I really cannot find the third ball. <:( I swear I tried!

Takeaway: this could be interesting as hide-and-seek, although the clone does not seem to be able to move by himself (apart from teleporting regularly). Some clues about the balls would be nice and interesting. I am also wondering how the clone is precisely a clone and not merely a simple enemy; how does he relate to the player? Is it merely physical appearance? And why do we have to find the balls?

Suggestion: find some mechanic that would make the clone’s behaviour correlated to the player’s actions, and connect the balls to that. It would come full circle, then. :) (Which is fitting for balls. XD)

the presentation is amazing

The visuals were pretty good. 
The map was big but nothing much to do, The clone also didn't really pose a threat, it just moved randomly.
Tried the game 3 times but was only able to get 2 colors every time, could have added some kind of audio or visual feedback, like if closer to a color. 

Nice try and good luck!