actually this kind of good, the battle is exciting, kinda repetitive, with the same pattern, with power of self confidence and smile (or some trust), you get boost up, typical shonen plot armor
still the story built with good concept (and yeah, slime have many probabilities to become godly), sadly the manga is axed, so the continuation is only from LN (which not translated yet), which we can't see how the slime evolve to