I fully agree on all your points! That stuff (more npc's, dialogue, direction) is coming in the post-jam version. I also have plans for the items to do something visually so it's a bit more clear on what you actually did with them. For the log, I'm going to make the river and waterfall downstream disappear visually since the cave entrance is supposed to be behind the waterfall. I did toy around with the log allowing you to cross the river on top of stopping its flow, so I can see the confusion!
Thanks for the feedback, and thanks for checking it out!