what is the difference between MMO games and multiplayer games?
MMOs are multiplayer games that can have hundreds to thousands of players on at the same time on the same world/server/channel/whatever. Multiplayer games don't have that many.
Imo, MMO is the games which require player purchase energy or wth like this by using REAL money if they wanna play more, and multiplayer is the games which requires u to purchase the Premium ver to play more effective but if not, u can still play as long as u want coz there is no energy system and not every multiplayer games has premium content, Am I get this right? XD
No. Having pay options doesn't necessarily mean it's an MMO. They're more likely to have pay options to offset server costs (among other things because the way they are guarantees or is dependent upon repeat business), but there are also multiplayer games that do have pay options such as Bad Eggs Online and Vortex Wars.
The main difference between multiplayer and MMO is in the name. MMO is massively multiplayer. That's the main difference, the amount of players you can interact with.
A big difference I forgot to mention is persistence. Multiplayer games are largely played in instances, i.e. you create a new room every time you start a new game. If everyone leaves the instance, the room no longer exists. In MMOs, some of the play might be in instances but there is also a larger persistent world that doesn't go away when you leave.
