Hey guys! My first post here .
So I have this small game development competition for highschoolers and I need to have a game idea and these criteria are prefered :
-3D (a must)
-A repetitive game ( not a long single player)
-A co-op side of the game
-Quite simplistic on physics and graphics
-Fun and addicting
Thanks in advance guys please toss in all your ideas!

I suggest you give this idea generator a try. It has already given me more interesting concepts that I'd be able to prototype in a lifetime.

I need to have a game idea

I somehow feel we have entered the twilight zone where such things like this might happen.

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@George1044 3d pong

A billiard game?

2 vs 2 Basketball, in coarse simultaneous turns. Every player controls a separate character, with a limited set of commands to change speed and facing and to interact with the ball.

I won't give you game ideas because I strongly believe that if you want to develop a video game even though it is only for a school competition.The idea as to come from you and motivate you enough to create it. This is how I design most of my concept.

That being said, if you are short on ideas go check some online idea simulator. I know many people use them in game jam to find new idea.

Try this one: http://orteil.dashnet.org/gamegen

But looking at your constraints only one game come to my mind. Rocket League maybe try to get some inspiration from this game.

Hi George, I totally agree with Liondinos thinking of your own game idea directly connects to how well/ how much you enjoy making the game. After taking part in loads of game jams, I find siting down with some friends, picking some random words from a dictionary and then start thinking about game mechanics that could fit the words, works great.

Keep the ideas simple, that way you can really concentrate on what makes them great ideas.

Good Luck and keep us informed!!

Seems like a 1st person shooter would fit all your criteria

A billiard game?

A milliard one.

What is the milliard you're expecting? It's the billiard with a table of 1 millimeter.

Play at molecular level and take part in physically non-usual action (with 3D glasses), yet the rules are the same.

"Fun and addicting".