M.U.G.E.N never had online play. For years the workarounds were screen-sharing tools, Parsec, or emulator-style netplay that needed both players to have the exact same folder. rugen loads the same MUGEN files and adds real online play, so you can fight a friend, a stranger or a whole bracket without copying anything by hand.

What you need

• rugen for your system: download it here. Windows, Linux (.deb, .rpm, tarball), macOS and Steam Deck are covered in the install guide.
• At least one character in chars/. Your old MUGEN zips and folders work as they are.
• Nothing else. No port forwarding and no matching rosters.

Step 1: add your characters

Copy your MUGEN characters (zips, rars or folders) into rugen’s chars/ folder and stages into stages/. Start rugen: it converts each one once in the background, and fighters appear on the select screen as they finish. The characters and stages guide has the details, including the one thing RAR files need.

Step 2: go ONLINE

Pick ONLINE on the title screen. The official server is already in the list. The first time, rugen asks for your consent to send your fighters to the server and your opponent; they are deleted after three days.

You get four buttons:

• QUICK MATCH pairs you with someone close to you in ping.
• RANKED does the same with an Elo rating and seasons.
• ROOMS lets you make a private room and share its code with a friend.
• LEADERBOARD shows the season’s best players and fighters.

Step 3: pick a fighter, any fighter

This is the part MUGEN players usually do not expect: your opponent does not need your characters. Each match opens a matchup screen. You both pick from your own folders, the server checks the pair and stamps it FAIR, UNBALANCED or BLOCKED, and the files sync in the background before the fight. A broken or overpowered fighter cannot sneak into ranked. How matchups are judged explains the rules.

Why it feels good

rugen uses rollback netcode, the same approach modern fighting games use. Your inputs show up instantly; when the other player’s input arrives late, the game quietly corrects the last few frames. The simulation is deterministic and tested so both machines always agree. The netcode page goes deeper.

Playing with friends on the same network

No server needed: ONLINE → LAN / DIRECT IP connects two machines directly. See direct matches.

Tournaments

Once you are comfortable, join a cup on rugen.dev/tournaments. Brackets are run by the server, and spectators can watch live from the game.

Questions? Ask on the help board. Everyone started with the same empty chars/ folder.