"That Time I Got Reincarnated as a Slime" is a typical "isekai". If you aren't already a big fan of the genre, stay away.

I guess it's fun to watch the character grow in power. But to me it didn't feel earned. The supporting characters and enemies don't put up much of a fight, and don't have interesting abilities or complex stories of their own. The reality seems to warp around to accommodate the main hero.

References to video games here I especially dislike.

Only watch it if you already adore the genre.