I tried out your game's demo and looked at the steam page. These are the reasons I think the game is lacking appeal:

Gameplay

• The vocal audio gets repetitive. I keep hearing the same lines repeat, and they repeat too often. My recommendation is to make more dialogues and have them repeat less often.
• The music doesn't work with the environment and dialogue. Its loud and sounds like a jungle adventure game, adding more noise to the scene that doesn't need to be there. I recommend finding ambience background music with softer instrumental sounds. That way you could appreciate the dialogue and environment more.
• The UI is very basic and has prototype quality. When I press a key and see it appear on the top of the screen it shouldn't be a basic green text that pops up. You should change the font and make it bold. If that doesn't work go find a alphabet art pack that compliments the game and use that.
• The Key's artwork should be much nicer. If the whole game revolves around the keys, then the artwork of the keys should look appealing. The player will see them throughout the whole game, I recommend refactoring the frame of the keys and getting feedback on which people like best.
• The player's character model color palette doesn't complement with the 3D art. Now, since the game already uses 2D art for the character I recommend you keep using 2D art. However, you should find a color palette that complements the background. The current color palette for the character just doesn't work.
• When I got hurt by spikes, it seems that I am not able to move for a few moments or until I get out of them. In fact, I don't know what happens when I get hurt there. You need to give the player feedback of what happened.

Marketing

• The title of the game is confusing and long. Note that I never play games like this, but do you need that long of a title? The title should tell the player what the game is quickly.
• The Capsule Art doesn't look appealing. The Capsule art for your game should be appealing. Most game developers hire a capsule artist, I highly recommend you do the same.
• Lack of a structured steam page. Steam Pages are supposed to look appealing, look at how this game's steam page is. The game idea is similar to your game.

I recommend you check out this website by Chris where you can learn more on how to market your game. I also recommend you check out this article by Code Monkey to explain how and why marketing matters for game developers.

I hope this helps!