The first time I tried running the game, it showed the first line of dialogue and stopped refreshing the window afterward, even while the audio was still demonstrating that the game was continuing. I did respond to someone in a browser chat box, but I don't recall any other rpgmaker games behaving that way when I've switched windows. It worked better after I closed and reopened the game, but then it froze on the first battle after I tried talking to the big blue creature, defending a couple times to see if something would change, and the talking again. I think it was when I selected the top choice that it froze, but it did go back to showing the general battle menu. Both times I was trying to talk with the friendly words (because the intro and goal gave me the impression I shouldn't be fighting things unless really necessary).
Like the previous comment said, the mushrooms in the first screen should have smaller collision areas. It's strange for the player character to not be able to stand behind them. The battle transition went really slowly for me as well and included a rather long time of only showing a black screen. I'll also add that the screens showing the known creatures went by too fast for me to fully view them.