If you didn't know, there is a new difficulty after hard; "Random". Doing this will change the chart of what week song your gonna play. I put the random difficulty on and went to ugh, the chart changed, it was like a fan-made chart. It wasn't the Ugh High Effort chart though.
Random mode actually randomizes all the arrows in the Hard Mode chart of the song. It does this with an algorithm to prevent too many double notes, and if you get a random map you really like, you can press Tab and then CTRL+C to copy the current seed to your clipboard so you can play it again at any time by pressing Tab on the main menu when Random is selected and pasting the previously copied seed with CTRL+V :)