Hey, I gave the game a go and it was an excellent nostalgia trip! It's a very well made game, that's a lot of fun and apart from it being kinda hard to find the yellow card key, I felt it was great.
The yellow card key forcing the player to backtrack kinda threw me, I hadn't needed to backtrack that far before so I ruled it out as a possibility at first. The vast majority of my playtime was trying to find the thing.
It might assist newer players, if the route there was somewhat sign posted? I don't mean in a 'this way to the yellow card!' kinda way but more like the door itself is sign posted but not the route where you find the key. I noticed a few people had this problem, it's why I felt I should bring it up.
I really like what's on offer. I'm really looking forward to the full game and I've made a video of the demo, to tell the people I know about the game.
I heard a certain someone has been reducing the amount of videos on this game, so I thought I'd help boost it, hopefully get it back to where it was and beyond!
Keep it up! :D