Hi,
First of all, I am new to this site, so my history and profile is non existence. No point checking them out.
Here is my proposal for your game: Dungeon Crawler RPG.
A board game where player choose a hero and enters the dungeon.
Heros will be collectible and different heros have different abilities and ways to play them.
And different dungeons have different objective and difficulty, with this two combination, you will have a game with endless replay ability.
There are two parts to the game, a cooperative mode where player fights the system. And a versus mode where players go against each other.
So here is what I am going to do if you gives me the job.
I will layout the core mechanics of the game. How it is played, what is the rule when it's single player, and what is the rule when it is multiplier.
I will craft 2 main characters for the game that player can play. (Given your offer and the time for the project.)
I will craft at least one map for the game. ( Which includes all the details of the map, monsters and boss)
I will craft a basic equipment system.
I will give you the direction of how this game should expend it'self beyond what I have crafted for you. (How to be collectible).
My timeline for this project is 10 days, I will make sure I deliver what I said above by the deadline.
Again, even though I am new this this site, but I hope I have shown you my seriousness and my expertise on game design.
Trust me, I will make your money worth.