16. A non-transitory computer-readable medium having computer-readable instructions thereon, operable to cause data processing apparatus to perform operations comprising:
receiving input from a user, the input directed to manipulation of virtual equipment in an interactive computer game, the virtual equipment being manipulated through the user's interaction with an associated representation;
determining a change in the user's skill level for interaction with the virtual equipment in response to the received user input; and
adapting a virtual equipment model having one or more variables associated with the virtual equipment to reflect the determined change in user skill level, the virtual equipment model governing how the virtual equipment behaves in response to the user's interaction with the representation, and where the adapting comprises:
if the change indicates that the user's skill level has increased, decreasing a sweet spot for a variable of the virtual equipment model; and
if the change indicates that the user's skill level has decreased, increasing the sweet spot for the variable of the virtual equipment model,
where the sweet spot is an area of a curve for the variable where the area is specified by a degree of deviation from an ideal value for the variable.