I was really surprised at his skills and creativity. Even experts could be fooled by his ideas about ■, and it could be said that especially △ and ◎ are new suggestions on the plot and perfect answers too.
I was astounded by his skills and sense of creativity. His ideas about --- will most likely deceive experts. Especially △と◎, being a new suggestion for the plot, can be considered the perfect answer.
I was surprised at his technique and sense of creativity. Even the experts might be tricked by his idea about ■. Especially △ and ◎ are the novel proposals for the plot and we can give him full marks, I suppose.