It is the fourth Harvest Moon game on Nintendo DS. Like previous titles in DS series, Island of Happiness utilises the stylus, and also features WiFi capabilities.
You can choose to play as a male character, Mark or a female character, Chelsea. The main character is an aspiring farmer who wants to begin a new life on a far away island. The story starts with the player boarding a ship that will take him/her from the city to an island to start a new life. Whilst you are on the boat, there's a violent storm at sea. The ship you are in is hit by a lightning bolt and gets destroyed.
A man named Taro finds you on the beach and checks on the main character, waking him/her up. He was on the boat with the rest of his family, and you are all now shipwrecked on this island. Taro takes Player to the top of island and finds an old abandoned ranch. He asks if you want to be the rancher of this island. You will automatically agree.
All movements and actions are done using the touch screen, with the D-Pad used to change/equip tools and items. The game uses Wi-fi to enable an online farm ranking service and an online voice chat session using the DS Microphone.
The characters of Island of Happiness are all new characters to the Harvest Moon franchise. Additionally, there are some characters to unlock when players meet certain requirements such as building up the island or getting a certain item.
In every Harvest Moon game, there are requirements to get married. The requirements for IoH are:
- Have met all main characters.
- House must be fully expanded.
- Own the big bed.
- Buy the Blue Feather.
- You already seen your chosen marriage candidate's black, purple, blue, and yellow heart events. NOTE: The events are not only required at that color, for example You can still trigger the person's Purple Heart Event even though his/her color is Yellow.
- The Church must be unlocked.
- Candidate marriage must have a Red Heart.
- Main article: Your Child (IoH)
Your child will be born 90 days after our wedding ceremony.
To have a child, the main character must get married.
After you get married, upgrade your house to "super size". 700 wooden lumber and 50.000 gold are required. Additionally, you can pay 80.000 gold if one (Player) doesn't have the lumber.
After upgrading your house, buy the baby bed. This costs 10.000 gold.
Your child will grow into three different stages. Their gift preferences also change as they age.
The candidates that the player does not marry has potential to get married to their rival. By watching rival events between the rival couples, there is a potential for rival couples to get married. After they marry, the rival couple will also have a child of their own. Unlike in Harvest Moon: Animal Parade, their child will never grow into child stage.
Shea, Mark, Chelsea and the Witch Princess do not have a rival candidate.
- Denny and Lanna can get married. They will have a daughter named Rosa.
- Elliot and Julia can get married. Their daughter will be named Kelly.
- Pierre and Natalie can get married and have a son named Jean.
- Vaughn and Sabrina can get married. They will have a daughter named Emma.