Instructions
Decide your game's genre before you begin working. Your audience will expect frequent swordfighting, so make sure to choose a genre such as role-playing game or perhaps action platformer. You can draw from examples such as the Final Fantasy series, Castlevania series or Red Steel. Keep in mind that making a game is a huge undertaking; it is best to stick with a relatively simple genre and game if you can.
Write your story and script. A simple genre such as platformer will not demand a particularly complex story. For a consistent theme, you should establish the game's setting as medieval Japan, though you could break out of this paradigm if you have a good enough idea.
Plan the player's weapons, armor, and other equipment. Players will expect a Samurai-themed game to have a focus on gathering and upgrading weapons, especially Katanas. Even if you are making a simple platformer, you should consider offering the player the ability to find upgraded weapons. You can use games like the Mega Man and Metroid series for examples of action platformers with frequent weapon upgrades.
Download or purchase video game maker software. Examples include: Game Maker 8.1, RPG Maker VX, or Stencyl. Each of these programs helps you create video games without needing any prior programming knowledge. RPG Maker is focused on role-playing games, while Stencyl and especially Game Maker are more open-ended. Pick the tool that best suits your genre and story.
Choose an image editor to draw graphics for your player, enemy, items and other miscellaneous objects. You can either use Paint, which comes free with Windows, or obtain higher-end graphical design software such as Gimp, Adobe Photoshop, or Corel PaintShopPro. Alternatively, you could search online for Samurai-themed graphics and import them into your game.
Download and import music in the style of medieval Japan to fit the theme.
Find or design tilesets that fit medieval Japanese architecture for your buildings. Tilesets are repeatable, segmented pieces of a scene that you can arrange in a map to your liking. You can use more generic tilesets when dealing with scenes outside of towns.
Construct your levels in your chosen game creator software using all of the resources you have gathered. Try to maintain a consistent difficulty curve; i.e., easy in the beginning but challenging by the end.
Save, compile, and enjoy your game. As long as you are not planning on selling the game, you can distribute it freely within online communities to help critique and improve your game.