World of Warcraft
"World of Warcraft" was first announced by Blizzard at the ECTS trade show in September 2001. Released in 2004, development of the game took roughly 4–5 years, including extensive testing. The 3D graphics in "World of Warcraft" use elements of the proprietary graphics engine originally used in "Warcraft III". The game was designed to be an open environment where players are allowed to do what they please. Quests are optional and were designed to help guide players, allow character development, and to spread characters across different zones to try to avoid what developers called "player collision". The game interface allows players to customize appearance and controls, and to install add-ons and other modifications.
Hearthstone
Of the game types they explored, Team 5 soon focused on the collectible card game approach, given that many on the team and in Blizzard had played such games since their introduction. The team found it natural to build the card game around the existing "Warcraft" lore; according to production director Jason Chayes, "Warcraft" was already a well-known property, and the depth of characters and locations created for other games in that series made it easy to create cards inspired by those. They also saw that new players to "Warcraft" may be drawn into the other games through playing "Hearthstone". The team was able to pull concepts and art from the pre-existing "World of Warcraft Trading Card Game", first published in 2006 by Upper Deck and later by Cryptozoic Entertainment; when "Hearthstone" was near completion, in 2013, Blizzard terminated its license with Cryptozoic as to favor their pending digital card game. The addition of heroes, an aspect from the previous trading card game, was found to help personalize the game for the player to allow players to discover useful combinations of cards for each hero.