I like what you have so far in the prototype, the puzzle was fun and the npc interactions worked great. While there was a lack of theming, I'm going to let it slide as this is a prototype and likely will have more in those categories in the next build of the game. As I mentioned in the survey, and on Discord, I came across a bug involving the small box in the corner near the exit of the prototype. Upon interacting with the small box using the left mouse button, it got stuck to the player character and it wouldn't let me put it down. This broke the game and messed up the collision and physics on rest of the boxes and made have to restart the prototype. I already addressed the speed of the player character, but something I wanted to add was the lack of music or sound. The silence made walking around the prototype feel empty, and I think needs to be added in some form in a future build.
After reading your devlog, I'm glad to see that you're taking the feedback you received into consideration, especially taking into account of being a solo dev. Talking to friends to help come up with mechanics is a great idea, just be careful to not go overboard on them as it might affect your scope. This is something we warned about yesterday during the overview of the production sprint, so I would highly recommend having a set of mechanics you know for a fact you want in your game and prioritizing those during the production sprint. I like the idea of having collectibles and I think it's a great example of something you know you want to add. Going back to what I said about the lack of music and sound, it's fine if you plan on adding that later, just make sure you have that planned out.
Overall, I enjoyed your Prototype. the gameplay was fun, and despite the game breaking bug with that small box, I was able to figure out the puzzle. The different ways to approach the box puzzle shows how you plan on implementing player's choice into your game. While there's a lack of art and sound now, I can see that you plan on adding it later and look forward to seeing it. I appreciate that your taking in feedback, but just make sure that you don't go overboard on mechanics and scope. Anyway, I look forward to seeing what comes of Everlasting.