The Beginning
After the preliminary cut-scene, you will fall down an incredibly long hole. Now you must make your way down the rest of this hole, all while killing the Skeleton Bombers that get in your way.

Catacombs
To simplify the explanation just a little, I have incorporated a map system.

This is a map of the next section. The path to the boss is marked in yellow. Follow that path if you want to just beat the boss. To get all of the extra items along the way, take the lavender path. The gray areas are hidden rooms. You must strike the wall with your whip to access them. The red dots are Heart Max upgrades. The orange items are Health Max upgrades. The light blue items are Magic Max upgrades. You can only get the upgrades that have lavender lines going to them. The other ones you will need more Magic Items to get to. The red squares are save points. Always save your game at a save point. Not only can you save your game but you can also replenish 100% of your health and magic. Be aware that I will not tell you to level up. It will be your responsibility to do so. I will also not remind you to go back and grab any extra items that you may have missed. You can stray from this guide at any time to get extra items you missed.

Follow the yellow line to the first save room. Save your game and heal yourself. Fight monsters in this first room until about level 3 or 4. Now, head to the next room. In this room is your first Magic Item, the Dash Boots. This item lets you dash when you double press left or right. Use the dash to get across the platforms and into the next room. In this third room just head straight through. In the next room are three extra items, marked by lavender lines. Grab these items and head up to the next room. Head left and slide through the narrow passage to get into the next room. In here is only one extra item. Grab this item and leave through the bottom hallway, sliding through the narrow passage as before. Back in the tall room, head up again. This time go right and grab the extra item. Now follow the yellow line through this room and the next. In this next room there are two extra items. grab the both and follow the yellow line to the boss. After felling the boss, head to the next room and grab the Double, a Magic Item that lets you jump twice. Now, head back through the boss room and to the bottom of the next room. Head to the left and use your Double to jump the ledges at the end. Don't forget to grab the extra item that's hiding behind the wall. Exit to the left.