I actually enjoyed the adventure-story format, and I thought the puzzles were tricky, but not impossible with a little observation and logic. There were several instances that required trial-and-error, which is a little on the frustrating side, but I disagree that it was really necessary with the moai. The first time I placed the three objects, and returned to the moai, it was easy to tell which were correct. All it took was switching the incorrectly-placed objects into the right locations.
As you continue to create these games, your drawing (a purely technical skill) will improve, as will your ability to write dialogue. You aren't doing poorly in either area, though they can only get better with time and practice.
I would be interested in seeing a little more depth and more investigation in your next game; it wasn't shallow, precisely, but the bulk of the game consisted of clicking around the area to move things in order to solve puzzles. I'm a big fan of mystery and detective games, and the genre gives you so many possibilities for plots, locales, and intrigues. I think more could have been made of this, satisfying as it was. Decoding the glyphs, interacting with the natives that were mentioned, searching for survivors, and so on would have added a greater sense of richness and scope. The glyphs might have imparted some obscure legend leading into the sequel; the natives could have provided hints about the island puzzles or the location of the plane, offered quests, or just given more background information on the island and the moai mystery; the survivors might have helped lead the detective to other resources or offered helpful information about the boy's possible location ("Just before the plane went down, I noticed smoke coming from the trees over there.").
These stories have the potential to be really engaging, and I look forward to the next one!