that's not what i meant. before you said:
"Level 1 - Health: 50 Armor: 25 Crowbar damage: 3
Level 2 - Health: 52 Armor: 26 Crowbar damage: 4
Level 3 - Health: 54 Armor: 27 Crowbar damage: 5
Level 4 - Health: 56 Armor: 28 Crowbar damage: 6 (Pistol Unlocked: Damage: 5)"
And what i meant was, if you unlocked weapons from only leveling and you could then buy them in a shop, questing wont be necessary, and that would be bad. What you should do is make rare weapons and unlocking weapons quest rewards.
Also, i can help out with the Multiplayer a bit, with a few ideas.
There are a few simple ways you can make your multiplayer rpg world possible. like my first idea is:
If you have 4-5 huge maps, you can get 4-5 different servers hosting one of the maps each and then the player would go to the maps according to his level, but then you would need to find a way to save the players xp when he quits or changes server.
If you don't like this method there is another way; like you can get 1 Big server and use the method some servers like css warcraft servers use, Where the players Xp is saved in the servers data base and updated every time he plays. But if you do this, you would need to find a way how to host all the maps in the server at once, cause I'm guessing you'd have more than one map in the mod.