This is a general concept which can be used for a variety of game types, I'll give an RTS and MMORPG example. Worlds at War: There are four (the number doesn't really matter) different worlds, or planes. They are each represented on top of one another, which is to say world one is under world two, is under world three, is under world four, which is under world one (its a loop). Each world has a different theme. For the sake of example, lets make it a gradient of magic to science. World one is pure elemental magic, with many an elemental wandering and many a mage. World two is more alchemical, with golems and alchemists and transmutation. World three is steampunkish, with some gas powered mechs and giant balloon-cities. World four is pure tech; very modern, with tanks and planes and whatnot. Each world starts with the same landscape, but with cities in different places. Which world four may have the city near an oil well, world one has no need for oil, instead placing the city near some magical lay lines. This is where it gets interesting: these worlds are at war. Each world is an empire, which recently discovered the others. And you can only travel up, unless you are world four, in which case you teleport to world one. So some specific people can transport those, and mayhaps those around them, up a world. But they appear in the same location they just left. If you teleport from what is, to you, a mountain up, only to find that the world above you has leveled the mountain to mine for ore, you will soon find yourself falling the ground below. How do you make this a game? Planar conflict (RTS) You start with a city, with a race specific resource type mine at your base (some overlap, like everyone uses some food and water, but only the more magically inclined use arcane stones). You gradually expand like in most RTSs. To make this more interesting, you will have to subdue some native AI players to advance. But soon (like, 10-20 minutes into the game) you get a unit which allows you to teleport guys to another world. Then the fun really starts. Because you can set up two way gates that allow transportation -- both ways. Some guys can teleport by themselves, and place the way gates, but you have to allow the enemy to attack you before you can really start pounding him in earnest. To make this a little cooler, lets give each race some units that can see into other planes, either up or down, in a small radius. Nether Expansion (MMORPG) You are a gifted one, one who can walk between the spaces of time and reality. You choose a world, which narrows down your class (no mage in the tech world). Soon after you start the game (after you get the hang of it, but keep it soon) you gain the ability to teleport to the world above you (or any world. It doesn't matter as much in this game). In that world, you can learn totally new skills, and get cool gear and new quests. I think it would be cool to have your steampunk army guy wielding a phase-rifle. Balance would be key here, and you'd have to ensure that it would be a pain to get access to really good gear of the plane you don't start at. -Doom. What do you guys think?

It has some interesting ideas, but has one great fatal flaw; if a player can only attack upwards, why bother, since the player above them is not an immediate threat? It encourages them to instead defend against the player below, who is probably doing the same thing. It's somewhat cyclical, and results in a game where nothing happens.

You need to give motivation for moving into the enemy plane (such as resources or abilities).

This perhaps needs clarification, but I think I did say that in order to make big attacks, you will need to open two-way way gates, so the enemy may be able to repulse your attack and make a counterattack.

Also, I don't think I mentioned this, but it was intented. The starting resources show up on EVERY plane. So even though the enemy won't necessarily need them, they have them. This makes an even bigger incentive to invade, since they most likely won't even have harvested your crucial resource.

I kind of agree that you need a better system for fighting down, so lets make a new ability: planar bomb. This bomb blows up one plane below you. You'll have to combine this with a unit that can see the plane below you to be effective, but you can also bomb enemy bases with it. This gives the player below you an even bigger motivation to secure the area around their base on your plane, since you can easily wreck it with enough bombs.

That's even worse, and doesn't solve the problem; why bother ever opening that gate until you're satisfied that your opponent below you isn't going to attack you any time soon - especially since now the opponent above you is able to retaliate.

Put a turtle in a big metal safe, and it's even less likely to show it's face.

There are numerous reasons why you would want to attack up. Number one, way-gates are temporary (a few minutes) but more importantly, destructable. From both sides. They have a bunch of hit points, but you can take it out if you have to. Also, the main resource you really want will be pretty quickly used up. There are only a few expansions for your race on the map. To increase resource gain, you really have to go and attack another player. Lastly, since the player above you can bomb the crap out of you if you haven't secured your base in his dimension, you really have to attack to at least secure that area.

Turtling may work, short term, but you'll quickly run low on resources and be in a perpetual state of worry about whether he is about to destroy all your workers with a planar bomb.

Interesting idea, but..

The worlds would have to be random each game for RTS. Otherwise id ptu all my defense at the lower worlds resource spot, making it impossible for them to develop from my worlds resource.

I would think that having any world be able to attack any other world would be better for gameplay and story. It just doesnt seem right that I can not attack the people attacking me. Or is the idea that forming an alliance with people above me to attack the one below me. If im world 3 and world 4 is below me. I should make my way up through to world 1, form an alliance with him and put some uber pounding on world 4. I wouldnt have to worry about anyone else attacking me cept for my ally. While the attack on world 4 is going on.

The gameplay is a bit skewed and very linear when it comes to strategy. Where making them 4 planets and each world can attack each other might take you a bit further. Also when im thinking of worlds on top of each other... just drawing out the landscape gets a bit ugly... how far below one is the other? Are they all on the same planet and jsut live beneath each other?

Like most RTS games, there would be multiple maps. Visually, this would look like a two-dimensional map. Some units wold let you see through the board one way or another, with a foggy effect that fills in other units. There would be a button that switches you down or up in worlds. It would be really hard to secure the main enemy resource spot, as it occurs in the same location as their base on another plane. So if you manage to secure it, you can planar bomb the crap out of them, making them have an even bigger motivation to expand in planes early.

I realize that my last post was a tad confusing. Expanding upwards from your starting base plane-wise is a very good move, since the resources start in the same place in every game, and because the enemy can bomb your base if you haven't secure the next level up. Your enemy can always try to go one level higher, though, and bomb your second base.

Sounds a little bit like Cave Wars : which was a 4x style game set underground , in a five level world : where you could create tunnels to the level above / below you and then move units through.

Hm. What is cave wars for/ how could I find it.