I see what you mean about the similarity to Frazetta's 'funny stuff' Sue - especially those rabbits. What's more it's made all the more noticeable by the American-style colouring of that cover.
Regarding Ron Embleton, it's worth noting that he got his own chance to illustrate Alice just three years later when her adventures in Wonderland were serialized in the educational magazine
World of Wonder.
To my mind, however, this version seems a bit rushed and cramped: definitely below his usual standard - besides which it has an off-putting slickness which makes Alice look as though she's strayed from the pages of Embleton's 'Oh Wicked Wanda' strip in
Penthouse!
By contrast I'd rate Jesus Blasco's interpretation amongst the best work he ever produced. I don't know if he did all the colouring himself but your mention of the background colours 'crashing together' in startling ways is spot on. Here's a truly spectacular sequence in which the whole scene seems to be viewed through a kaleidoscope:
...And Alice's encounter with a 'magic' mushroom is positively hallucinogenic (this was, after all, just three years after the 'Summer of Love'!).
Finally, an electrifying sequence from 'The Enchanted Lion' where Blasco experiments with avoiding the use of solid black altogether in two panels - thereby producing an utterly stunning effect that seems to jump right out of the page!
- Phil Rushton