NOTE: This is some of the description about the plot taken in the game, but it's altered due to grammatical errors.
Far in the future, in the recent past a giant meteor explodes near the Earth, and a lot of the diamond crystals has landed on Earth. Giana has started to get the diamonds, and she's done it!!
However some reports were recieved, that the biggest diamond of the meteor fell on the Troll's Land, Giana didn't know this for a while! She decided to get this too. She took four kinds of weapons, but this was spread on the Earth during she flew by her spaceship above the Troll's Land.
What a pity!!! She had to start without guns, but it couldn't be impendiment. This adventure has begun again...
The player controls Giana and collects diamonds. Unlike most of the installments of the series, it doesn't have any incorporated elements from Super Mario Bros. And you need to collect chests containing four weapons; which is the missile, ninja razor blades, knives and a rocket (known as the Wall-Breaker) that can be used to eliminate enemies.
There is a sequel mentioned known as I Want More Diamonds 2, however this never made to be developed by the creator of I Want More Diamonds.
It is one of the two Giana games to take place outside the Dreamworld, the other one was Hard 'n' Heavy (formerly Giana 2: Arthur and Martha in Futureworld).
The game's storyline reveals that Giana owns a spaceship.
This would be mentioned again in the mobile phone port of the Great Giana Sisters.