I've played through the game and got stuck at the section of the party the character says it's incomplete, but even after getting the necessary items they still say the same things, and there is no more hidden items or hints to give me a direction. I quit and came back into the game, but after doing that it seems like the items that I had were missing from the table, and the basket in the gas station was missing too so I had no option to try and get the items again, I think there might be an issue with tha...

is there a key outside ? the gate rattles but doesnt open

The developer is still active from time to time and I can tell this was a fun passion project. Obtuse at times, but the dev makes up for it. See below (had an oven question)

I've seen walkthroughs that show the answer to the puzzle so I know what it is, but none of them showed how to actually find the solution. I know it's not just the diagram on the ski lift, at least not by itself. I found a locked door in the ski lodge, but I couldn't find any key after scanning the place. I saw the numbers on the posts but I needed more info to do anything with that. Can anyone point me in the right direction to find the answer?...

Zone of Lacryma devs, no way.