First I thought: "Well, this seems very basic and boring." Then I saw that this was your first game! Compared to the steaming piles of garbage I created when I was starting out, and even now, then this game becomes absolutely amazing!
It does miss some music and propper sfx but apart from that anything is there.
I also really enjoy the fact that every slime can die, but as long as one's on screen you survive. This feels like teleporting around the map, controling different slimes trying to create a slime army!
What makes this game impressive is that it is your first one. And you can feel extra proud of yourself for creating an actually playable game as your first, rather than a red screen that says pen!s in blue letters. Yes with the exclamation mark