It's an interesting concept, and I had fun playing it!
Here are some ideas and suggestions, but remember you hold the power in the end.
- I would recommend making the "New Players: Start at 1st Nightmare" a little more prominent. I started at the 2nd nightmare because I thought "that's what I'm critiquing". I was so confused on what was happening; until I realized that I should start at the beginning.
You could do this by having the first few seconds of the video to direct newcomers like this:
Of course this was a quick outline, and the wording could use some work. But I hope you understand what I'm trying to suggest. Once you make more videos, you don't want newcomers to be pushed away because they started at the wrong video.
Side note: I
REALLY like the music. Did you make it yourself

?
- It's also frustrating to start at the very beginning once you mess up (especially near the end).
If you're trying to make it like an arcade game where they have to restart, I would say
why? People could just click back to that part of the video instead of going through the whole game again. You don't want viewers to have to jump through more hoops just to play your game.
You could maybe have checkpoints, or have them start at the beginning
of that section (instead of the beginning of the game)
- Here's a little suggestion that might be interesting. You could try adding a story! You could add it in the game itself, or make it on a separate video. (Ex// League of Legends tells it's story outside of the game whether it's in that newspaper thing or a cinematic video). You could also use the story of the game as a channel trailer too!
- Any other critique would be from the platform you're making the game on. There are drawbacks to making the game on Youtube (ex// waiting too long on a level and so one of the buttons automatically get pressed)
These things could be fixed if you made it on something like flash; however, it's your creative decision. I have no say in what platform you choose to make your game on. I think it's unique and cool that you're making it on youtube. Just know that you'll have to accept the flaws on a weaker platform.
Overall, great game! At first it seemed simple, but later on I could see how complex it could get. Can't wait for the next nightmare!