public void RemovePickups(IEnumerable <Pickup> pickups)
{
foreach (Pickup pickup in pickups)
{
if (pickup.Amount == 0)
{
continue;
}
Pickup existing = Pickups.FirstOrDefault(p => p.Id == pickup.Id);
if (existing == null)
{
continue;
}
existing.Amount -= pickup.Amount;
}
}
