Hi!
Game is meant to be challenging, it is a die & retry, so it's normal if you experience that, like any hard die & retry, you'll learn patterns from your different tries, and then you'll succeed the level! It usually takes up to 10 tries in general for people to clear this level the very first time they experience the game.
Don't worry, you'll manage to pass it, try to find safer spots, and once you're used to controlling the triangle well, you'll need to move faster/react faster in order to dodge everything without getting it!
Also, we have a group of alpha tester helping us finding out the proper balance for the game, so it's challenging, but fair, this is the introduction level to the game you're experiencing during this demo, so it should be fairly easy to complete
Sincerely,
InsaneHawk, creator of Rhythmy