I thought that it might be possible to connect two players each controlling an object as the basic idea. As in the multiplayer pong, except that instead of having the bars were the characters.
This is already possible.. see the "Dungeon Escape" game in the tutorial.
It would be possible to connect two players each with an object under its control and without it being very difficult with construct ?
Yes it is possible, but the implementation is currently difficult in Construct. As Newt mentioned dealing with lag is a tough problem with multiplayer and even a bigger issue with an MMO. Right now you have to manually handle lag in the game. <----------- Alot of work!
You also have to deal with synchronizing all of the game elements. For example, have you ever shot somebody in an online shooter to find they are still alive? That is because to your computer (simulation) they were in range, but to the server they had already moved... or the other guy is cheating.
If you aren't careful all of the power of Construct will be lost because the built in behaviors, etc can't be used. The above is why it is important for you to understand the tutorial to know how much work will be involved. If you still decide to press ahead I'd be willing to offer advice, but I'm just too busy to be a member of a team.