These are the major unique features in MouRO, the stuff everyone should know about.

Monster Difficulty System - The famous @diff! No map is too easy with mobs able to level up. Level 100 porings, random higher level monster spawns, it is all explained here.

Parties - One of MouRO's main features is that we are party oriented. Here you can find all the info about why partying is preferable to soloing here.

Events - Even though there are no Event-GMs, there's a few things inside the server that let you organize events.

Public Commands - A list of @commands. @options provide many unique features such as auto-spell reuse, party-target for support skills, auto-target for offensive skills (such as Monk Combos). @info allows you to see many hidden stats in normal RO (cast time etc).

Character Sprite Customization - Separate aesthetics from function and "disguise" any equipment as another piece, even make combinations that are impossible normally.

Memory Rollback System - The Memory Rollback System (MRS) allows you to temporarily lower your level to let you party/help people who are lower level than yourself.

The Test Server - Using the test server you can try out builds, equipments, and generally play around as a Game Master without affecting one bit the main server.