表示喜怒哀乐等强烈感情的句子叫做感叹句,感叹句句末常常用感叹号,用降调,句首多用how和what,后面接陈述句的语序.
how在感叹句中可以修饰形容词、副词、动词等.
How beautiful it is!
How tall a boy he is!（注意how修饰形容词,放在不定冠词a之前）
How well the clothes fit!
How I missed you!
How wonderful it is!
How strange is his appearance!
what在感叹句中,可修饰名词,名词为单数可数的,用what a,不可数的以及复数的名词之前用what,如：
What a good opportunity it is!
What a tall boy he is!（what修饰的不是形容词tall,是名词短语a tall boy）
In what a mess I am!
What fools they are!
What beautiful pictures they are!（what修饰名词短语beautiful pictures）
所以你给出的句子的同义句转换应该是：
What an exciting game it is!
希望我能帮助你解疑释惑.