Um. So I'm not sure what this book was about.
Potentially it was about either time travel or about a father-son relationship. WHO KNOWS.
There's a lot of words that reminded me a bit of The Quantum Thief, in that it's a bunch of words that mean "this is how time travels happen" but I think Quantum Thief pulls it off better.
That's not to say it wasn't good of funny, it's just that it made me go 'huh?' and be slightly confused about things, so that I'd have to re-read it a bit more. I think it was just trying to be a bit too clever and so when you're tired it just doesn't flow as well as it should.
Anyway, as mentioned, it was pretty funny. But then it would have really serious turns and so the tone kind of went up and down like a wave, which was also kind of jarring. I think my favourite character was actually the non-existent science fiction dog, who is barely in it.
The actually main character wasn't all that likeable, but there is a really funny line about how 35/37 versions of him that he has met have been assholes, so what does that say about him? Possibly the funniest line in the book. That's the main character conceit (that he's a bit of an asshat) and so a lot of the humour stems from him doing the wrong thing a lot time. But that does get a bit old.
When it hits the last bit of the plot (where he has to get himself out of a time loop), almost all the humour falls away and it is really about this father-son relationship. Which in way, makes little contextual sense to me. I know it is referenced throughout the book (it's the main reason for him basically being a rut in his life), but it is such a heavy u-turn for me that it felt out of place.
Despite all that, it was pretty short and mostly amusing. It does a lot of things with time travel which I haven't seen before (and multi-universes) which was fun. So, I think it's alright in all but just a bit wobbly. Maybe I'm just also really tired from travelling and can't quite capture what was good about. Shrug