Valley 1 was pretty easy. I found myself never dying on the second-highest difficulty. Tidalis is pretty easy to not die in, because even if it is turned up to really hard, you can generally at worst live. You can't really make combos if you're bad but it's no Meteos in the 'screwing you over when you make a mistake' front. AI War is really complex, and it is challenging on normal mode, but it allows the difficulty to go as low as basically turning the AI into something as hard as a fluffy bunny.
Valley 2 kinda came out of nowhere for me, because it's one of your games where there isn't really an option to just make the game trivial. I found it just like twice as hard as every other game you guys have actually made. It's muuuuuuch more awesome now rather than alpha on the 'turn the difficulty down and you'll survive' front, but it's still way harder on average than your other games, I find. I can actually die repeatedly on difficulty levels lower than the default normal mode if I make a simple mistake.