Is My Game Too Difficult?

My biggest game project, Gunventure, has been considered extremely difficult for most of my play testers. I don't want the game to be too easy, but I also want the game to be fair enough so that it feels fun. Is there anything I can do to the 1st island to make it more reasonable for newer players?

This is the game link: https://microstudio.io/codecat1/gunventure/