Yes, there is a height restriction. It is certainly over 1 metre, l think it might be 102 cm or 106cm,something like that, l can't remember exactly what the CM said it was, just that my DS (3) was too small. She said it has some bits that young children might find scary.
Reading the report about the nausea thing makes me think twice about Crush... the spinning in the dark thing may be too much for my boy-o, even if he is tall enough.