Hm. How do I describe this show in a sentence that is both logical and … sane in any matter or form? How about: 'if You saw any of the shows in the quartet, watch this series Goddamnit'? Yeah. It sounds about right.
First - the story.
Ok, so the story is inconsequential to the series. It really is just a way to put all the heroes from very different worlds together.
Having said that I did like its simplicity. There are stories that are dumb because the author had no idea what he/she was doing and there are stories that are designed to be simple. This show is the latter.
Second: the animation.
The animation is .. ok I guess? This series is basically ‘fan service, the anime! Isekai edition’ so I had no real expectations and boy - were they met!
Third: the sound.
See the ‘animation’ part but change ‘animation’ to ‘sound design’
Fourth: the characters.
Ok, so the characters are awesome because if they weren’t they wouldn’t be in this fan service anime. So the question is: how well do they work together, even if they are from different shows??
The answer is … pretty well actually. I was really surprised by how well the casts from VERY different shows work together. If this was an original series – I’d say the characters were designed to work with each other in perfect harmony.
Verdict: It's a lighthearted comedy with lots and lots of fan service. Do check it out if You like any of the shows involved in it. Hell – do it even if You don’t and then check the source material.