Steps to reproduce:
1. Download and launch attached project "Game $1.zip"
2. Open scene "1" and press play
3. In game press "Play" to start the game and click on screen to walk
4. Walk a bit until you encounter an enemy, then circle around him until you see artifacts (see attached screenshot)

Workarounds:
1. Using point filtering + disable Anti Aliasing
2. Pack the sprite sheet with our sprite packer within Unity
3. Recreate the sprite sheet with 1 or 2 pixel padding between each sprites