I don't know what the problam with my code

I made a simple 2d game and made a script that will kill the player when he’s touching the lava, but the collider didn’t work.

download:first game.zip - Google Drive

the code is in c#.
(it’s my first game, I know my code is bad)

Most people won’t be inclined to download your files. You should paste your script directly into your post using code tags. That way we can read your code easily, and it will be available for anyone else who finds this post in the future.