self.clip.text = [NSString stringWithFormat:@"%lu/%lu", (unsigned long)ammo, (unsigned long)maxAmmo];
self.levelLabel.text = [NSString stringWithFormat:@"Level %lu", (unsigned long)level];
self.lifeAmount.text = [NSString stringWithFormat:@"%d/%lu", health, (unsigned long)maxHealth];

- (void)setUpInventory {

    CGFloat rowOffset = self.frame.size.width / kInventoryColumns / 2;
    CGFloat colOffset = self.frame.size.height / kInventoryRows / 2;
    NSInteger count = 0;

    for (int row = kInventoryRows - 1; row >= 0; row--) {
        for (int col = 0; col < kInventoryColumns; col++) {

            SKSpriteNode *inventoryThing;
            if (count < [self.player.inventory count]) {
                inventoryThing = [SKSpriteNode spriteNodeWithColor:[UIColor greenColor] size:CGSizeMake(rowOffset * 2 - 4, colOffset * 2 - 4)];
            } else {
                inventoryThing = [SKSpriteNode spriteNodeWithColor:[UIColor redColor] size:CGSizeMake(rowOffset * 2 - 4, colOffset * 2 - 4)];
            }
            inventoryThing.position = CGPointMake(col * (self.frame.size.width / kInventoryColumns) + rowOffset, (self.frame.size.height / kInventoryRows) * row + colOffset);
            [self addChild:inventoryThing];
            [self.inventorySprites addObject:inventoryThing];
            count++;
        }
    }
}