b1
-Negative guild join fees make people very rich very fast.
-Fighting someone PvP, running away, going to a blankwhite pvp.php page, getting accused for hacking, and gaining XP?  It works.
-http://arcoria.net/attack.php?url=GraveYard.php&enemy=1&skill=2, copying this URL (dependent on location) lets you heal even if you don't have enough mana.

b2
-Talking to what's his face, the guy that wants you to talk to Elvis, talk to him twice in a row without talking to Elvis and he's pretty happy about it.
-Editing the skill value lets you use skills you haven't unlocked yet (http://arcoria.net/attack.php?url=GraveYard.php&enemy=1&skill=NUMBER)

b3
-Shop "Amount" value doesn't make sense, it doesn't go down if you buy an item.
-Changing the item ID in the Buy URLs in the shop allow you to buy items not there (notably id=12 which is the Diamond Ring)

b4
-Refreshing after a battle still nets you extra XP.
-http://arcoria.net/heal.php?url=game.php heals you at the cost of 5 gold.
-Refreshing the death page causes you to lose more gold/XP.
-Dying gives you 115/100 HP for some reason.
-You can join any guild uninvited by editing the URL: http://arcoria.net/join_guild.php?id=NUMBER