Pretty cool game, though a bit difficult to understand at first.  I eventually realized that clicking on the slimes reduced their size and teleported them and that fully destroying them would reward a point.  I agree that adding a lose condition or a way to build a combo would make for more engaging gameplay.

Does it go on forever? Why do I only get points for the smallest slimes? So many questions...

Could quite easily be made more fun and more playable. Currently it's just pointless (pun intended) clicking. Something like adding a limit of how many slimes can be on the screen or the player will fail. Maybe add point multiplier when clicking the same colour slimes in a row.

Nice touch that you had two options for the language even though there barely even was any text in the game :D