Game system, server system, processing method, and information storage medium

1. A game system comprising:

a memory that stores information about a plurality of items used during a game, the plurality of items stored in a data structure in which the plurality of items are linked so as to have one or more parent-child type relationships; and

a processor programmed to or an application-specific integrated circuit (ASIC) configured to:

perform a game process;

set a lottery range of a lottery process, the lottery range of the lottery process specifying a range of items among the stored plurality of items used during the game process that are subjected to the lottery process, wherein the lottery range is set so that a child item is included within the lottery range of the lottery process when a parent item has been set to an acquired state or an acquirable state;

change the lottery range of the lottery process based on player-related information;

select an item from items belonging to the set lottery range by performing the lottery process; and

perform an item acquisition process that allows a player to acquire the selected item.

2. The game system as defined in claim 1 , wherein the player-related information includes at least one piece of information among input information input by the player, status information about the player, game status information about the player, and charge information about the player.

3. The game system as defined in claim 1 , wherein the processor is further programmed to or the ASIC is further configured to: change a lottery count of the lottery process based on at least one piece of information among input information input by the player, status information about the player, game status information about the player, and charge information about the player.

4. The game system as defined in claim 1 , wherein the processor is further programmed to or the ASIC is further configured to: change at least one of a duration for which the lottery range of the lottery process remains changed, and a duration for which a lottery count of the lottery process remains changed, based on at least one piece of information among input information input by the player, status information about the player, game status information about the player, and charge information about the player.

5. The game system as defined in claim 1 , wherein the processor is further programmed to or the ASIC is further configured to: change at least one of: the lottery range of the lottery process, a lottery count of the lottery process, a duration for which the lottery range of the lottery process remains changed, and a duration for which the lottery count of the lottery process remains changed, based on information about a team to which the player belongs, or player-related information about another player who belongs to the team.

6. The game system as defined in claim 1 , wherein the processor is further programmed to or the ASIC is further configured to: change the lottery range of the lottery process so that the lottery range of the lottery process is set based on an item that has been set to the acquired state or the acquirable state.

7. The game system as defined in claim 1 , wherein

the plurality of items are classified to belong to one class among first to Nth classes, and

the processor is further programmed to or the ASIC is further configured to: set items that belong to Lth to Kth (1≦L≦K≦N) classes among the first to Nth classes to be a lottery range setting target when a level of the player corresponds to the Kth class among the first to Nth classes.

8. The game system as defined in claim 7 , wherein the processor is further programmed to or the ASIC is further configured to: change the lottery range of the lottery process so that the lottery range of the lottery process is set to items that belong to a class selected from the Lth to Kth classes based on the player-related information.

9. The game system as defined in claim 1 , wherein the processor is further programmed to or the ASIC is further configured to: perform a level change process that changes a level of an item that has been set to the acquired state or the acquirable state and has been selected by the lottery process.

10. The game system as defined in claim 9 , wherein the processor is further programmed to or the ASIC is further configured to: change the lottery range of the lottery process so that the lottery range of the lottery process is set based on the item that has been set to the acquired state or the acquirable state and has been subjected to the level change process.

11. The game system as defined in claim 1 , wherein

the processor is further programmed to or the ASIC is further configured to: select an item from the lottery range of the lottery process by performing the lottery process on a condition that the player has performed game play, or has finished the game play, and

the item acquisition process includes:

changing acquisition determination points of the item that has been selected from the lottery range, and

allowing the player to acquire an item for which the acquisition determination points have reached a determination threshold value.

12. The game system as defined in claim 11 , wherein the lottery process includes determining a change value of the acquisition determination points of the item that has been selected from the lottery range.

13. The game system as defined in claim 11 , wherein the processor is further programmed to or the ASIC is further configured to: set at least one of a change value of the acquisition determination points and the determination threshold value based on at least one piece of information among input information input by the player, status information about the player, game status information about the player, and charge information about the player.

14. The game system as defined in claim 1 , wherein the lottery process is a random sampling process that generates random number information, and randomly samples an item based on the generated random number information.

15. A server system comprising:

a processor programmed to or an application-specific integrated circuit (ASIC) configured to:

perform a game process;

set a lottery range of a lottery process, the lottery range of the lottery process specifying a range of items among a plurality of items used during the game process that are subjected to the lottery process, wherein the plurality of items are stored in a memory in a data structure in which the plurality of items are linked so as to have one or more parent-child type relationships, and the lottery range is set so that a child item is included within lottery range of the lottery process when a parent item has been set to an acquired state or an acquirable state;

change the lottery range of the lottery process based on player-related information;

select an item from the items that belong to the lottery range by performing the lottery process; and

perform an item acquisition process that allows a player to acquire the selected item.

16. A computer-implemented method comprising:

performing, by a hardware processor or an application-specific integrated circuit (ASIC), a game process;

setting, by the hardware processor or the ASIC, a lottery range of a lottery process, the lottery range of the lottery process specifying a range of items among a plurality of items used during the game process that are subjected to the lottery process, wherein the plurality of items are stored in a memory in a data structure in which the plurality of items are linked so as to have one or more parent-child type relationships, and the lottery range is set so that a child item is included within the lottery range of the lottery process when a parent item has been set to an acquired state or an acquirable state;

changing, by the hardware processor or the ASIC, the lottery range of the lottery process based on player-related information;

selecting, by performing the lottery process by the processor or the ASIC, an item from the items that belong to the lottery range of the lottery process; and

performing, by the hardware processor or the ASIC, an item acquisition process that allows a player to acquire the selected item.

17. A non-transitory computer-readable information storage medium storing a program that, when executed by a computer, causes the computer to:

perform a game process;

set a lottery range of a lottery process, the lottery range of the lottery process specifying a range of items among a plurality of items used during the game process that are subjected to the lottery process, wherein the plurality of items are stored in a memory in a data structure in which the plurality of items are linked so as to have one or more parent-child type relationships, and the lottery range is set so that a child item is included within the lottery range of the lottery process when a parent item has been set to an acquired state or an acquirable state;

change the lottery range of the lottery process based on player-related information;

select, by performing the lottery process, an item from the items that belong to the lottery range of the lottery process; and

perform an item acquisition process that allows a player to acquire the selected item.