I've been thinking about building a management / tycoon game about managing a shopping mall, something similar to Theme Hospital or Rollercoaster Tycoon but smaller in scope.

I've never done a game design document before, but this should be something like that, albeit probably shorter and denser. 

All critiques on the design and game are more than welcome!

General description

In the game, you take on the role of a manager of a shopping mall. Your goal in the game is to have the mall fully occupied by sellers, have enough customers, maintain and decorate the common spaces, and, of course, to make profit.

The game is played from a top-down view, orthogonal or isometric. The game is mostly designed to be played with a mouse and keyboard, but gamepad and touch-screen support may be explored.

At least in the first versions, there will only be a sandbox gameplay option, with randomly generated shopping mall layouts and other parameters. In the future, a story campaign can be designed, but it is currently not a requirement.

Gameplay

Most of the game is played from the top-down view of inside the shopping mall. From this view, the player can, for example:

• Assign / unassign shops to lots
• Decorate the common spaces.
• Upgrade lots according to different shop owner requirements.
• Hire maintenance crew

The game is also considerably menu-driven. Some of the menus include:

• List of shop owners who are looking to move in
• Financials view
• Crew management view
• Mall upgrades view

Shops

Clicking on empty lots in the mall, the player can select from a list of shop owners who want to move into that space. The shop owners can have different requirements, like rent, specific facilities (like restaurants needing water connections, gaming cafes needing high-speed internet, etc.), amount of foot traffic, etc.

The shops can move out if some of the requirements are not met, like not enough customers, expensive rent, too many competitors in the area, etc.

Financials

The player is constantly balancing the different financial aspects of running a shopping mall.

Some of the revenue streams: rent from shops, convenience machines in the common areas, advertising in common spaces, etc. The player can set most of these values themselves.

Some of the expenses: electricity, building maintenance, internet access, personnel, etc.

The player can make bigger purchases to offset these costs (for example, buying solar panels on the roof that decrease the electricity cost in the future).

Enjoyability

By for example placing decorative items in the common spaces of the mall, the player can improve the enjoyability score.

The score has a global average and also a tile-based score, so for example, placing a decorative tree will increase the enjoyability score of X tiles around it.

By having a higher enjoyability score, it will attract more customers to the mall. The shops can also have a high enjoyability score as a requirement.

Unkempt common spaces can reduce the enjoyability score.

That's pretty much everything I've been thinking about to be included in the game. Would love to hear any feedback on it!