Won many battles, bought a new castle, then built a new computer after I moved and no longer have my old one. The things you buy are saved client side, so I have to buy it all over again.
lame.
The hard badge is a lot easier than people are making it out to be.
Just make an all defensive/castle building deck. If you don't get builders or good cards on your first turn, reset.
Use lots of all bricks, add bricks, all crystals, add crystals to make up for lack of workers, and thief(s) as your only sword cards.
I got the "Hard" badge fairly simply with a gimmicky, castle building deck. All of my cards were to build the castle up, with no offensive cards at all.
The only 'sword' cards I used were a couple of thief cards.
I used wizards, add bricks add crystals, magic wall, Magic defense, all crystals and pixies to build up the castle.
I used builders, and all the castle building cards, and a mix of wall cards for a little defense while I build up. No offensive brick cards were used.
Gimicky decks work well for the 5 multiplayer wins. I made a deck where I removed all offensive cards, and focused on building my castle. The only "sword" card I had was a couple of thieves. I had a decent amount of crystal cards, mainly for the Fairies, and a ton of brick cards.
A good way to get your multiplier to 80 is to constantly be doing small hops. Practice your angles so that you can always hop into upcoming gates. The only time you should really be skiiing and not hopping, is in tunnels.
If it gets really hectic, launch yourself into the air, and you'll keep the multiplier going.
I only had to escape once, but I liked the game.
I didn't bother with offensive magic. I would stack attack power items and basically ignore other stats. I bought as many health potions as I could afford, and once I learned healing Magic I'd buy mana pots as well.
I actually didn't get the '10 Artifact' badge until after I beat the last boss. Don't worry if you are close to the end, you don't have to use the wings to get this badge, as all your artifacts will get added after the bosses defeat.
 "Forge of Gods"){kind=icon}
 "Flood Runner 3"){kind=icon}
 "Swords and Souls"){kind=icon}
 "Sieger"){kind=icon}
 "Castle Wars 2"){kind=icon}
 "Hello Worlds!"){kind=icon}
 "Depict1"){kind=icon}
 "Robot Wants Fishy"){kind=icon}
 "Solipskier"){kind=icon}
 "Coma"){kind=icon}
 "The Enchanted Cave"){kind=icon}
 "Chase Goose"){kind=icon}
 "Liquid Measure"){kind=icon}
 "Remnants of Skystone"){kind=icon}
 "Help! It's the Unfinished Shadow Game"){kind=icon}