How was the fight in Japan more challenging for Americans than the fight in Germany?

It was tougher logistically and physically.

Explanation:

In Europe there were modern allies that could assist America. This combined with Germany's less fanatical ideology, they were willing to surrender when they had little hope. Japan was determined to fight to the last man and we had to ship resources thousands of miles across enemy waters against enemies who were highly entrenched and had time to prepare.