It's come to my attention that the game is no longer on the app store, so here's an apk that other people have used to download the game: https://m.apkpure.com/br/slime-slasher/com.fiveminlab.slasher

I haven't used it myself but I have no reason to doubt its validity and it shouldn't cause any problems with your device, so enjoy!

BlueStacks is recommended if you'd like to try playing on your PC