Source of Madness doesn't explain anything to the player. It's down to you to work out the overall goal, how to\u00a0unlock new skills and achievements, and what all the scary-looking icons and doorways do around the world. This guide explains the meat portals, those circular meat shapes that you'll pass now and then, do.\u00a0 What do meat portals do? Screenshot by Gamepur The meat portals are doorways to what equates to a challenge room in games like The Binding of Isaac. These rooms contain a treasure chest that will only spawn once you kill everything inside, but that's not as simple as it sounds. As soon as you enter the meat portal room, horrific monsters will spawn around you and throw themselves towards you. Be prepared for a fight when you go into these rooms because the monsters will destroy you if you're not. The smaller meat portals only contain a few little enemies that aren't too tough to kill. However, the treasure from these rooms is generally worse than your starting equipment. The only advantage of going into them is picking up an item with a new damage type, such as fire. Once you leave the meat portal, having killed the enemies or not, it will have disappeared, so you can't go back inside. If you want to guarantee that the reward from a meat portal is better than your current equipment, then you need to wait until you find a giant one \u2014 these are rare, but they do exist. Given that these meat portals are larger, the enemies inside are also larger and have more health. These enemies are minibosses that you'll have to kill before your reward drops. The enclosed nature of the meat portal room means that the fight is much more challenging and may not be worth it with only starting equipment to your name. The reward may be too tempting, though.