Just for fun, I thought I'd try this level out on Crazy with a minimal load out.
This is what I ultimately used:
I first tried with only common cards (Poison instead of Volcano, then Centurion and Oni instead of Valorius and Clarion Call, GOT instead of Mana) but that only got me as far as wave 4. It had promise, but mana generation was just too slow.
Then I tried with the above layout but with Poison instead of Volcano. A few enemies snuck through around wave 5 though so the finish was only 2 fleurs. Poison upgraded to 2-0 or 2-1 just didn't do enough damage early on and I didn't have enough mana to get up to a more effective 3-2 or 3-3 until late.
I figured even though Volcano is rare, it's a standard card that everyone gets at the beginning of the game and in fact I didn't get Poison until half way through the Avian territory so it seemed fair in my mind to substitute those cards. Same with Valorius and Clarion, they are important standard cards that everyone will have, although maybe I will try again later without these two.
Mana felt like a cheat card for sure though, but I had to focus on getting it to 2-1 ASAP in order to get enough upgrades in to cast spells a little faster. I don't think I used Freeze more than 3 or 4 times, but constant Healing Spring was important.
The other thing to mention is you need Thor's Hammer at the entrance in wave 1, so I borrowed a friend for that.
Can anyone win with three fleurs with a lower powered load out? :)