Last Room
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.

Not much is it. Well, congratulations. You have made it to the end of the game. To get to the extra item, head to the lowest section of the area, and spin whip the floor. Head to the upper-left room to fight Dracula.