The core gameplay loop of my game will consist of three parts:
Traversal of the city
Repairing broken objects
Inventing & Upgrading your inventory
These all break off to have their own mechanics, the first of which is movement. Movement will start off relatively constricting. In a game focused around maundering through a city, this is only to make the gameplay immersive and rewarding. You main mechanics to start with will be climbing and jumping. But the core concept to remember is that the character will have his tools on him this means he won't be doing any crazy parkour or jumping huge gaps at full sprint.
Secondly, the repairing mechanic will revolve around what item you are fixing, each type of item will have its own category of mini game you will have to overcome to fix the item, the example I show here is a faulty electronics device where you will have to analyse which wires are faulty cut them out and replace them.
you would have to follow back the wires which are torn and cut them to proceed. Each type of mini game will have a short tutorial in your handbook (main menu) incase you don't understand or need a refresher.
Lastly it comes to the Upgrading system. for completing repairs you will be give money you can invest in research and development of new inventions. these will dramatically change gameplay adding new mechanics to the traversal stage of the gameplay loop. For example you can make a grappling gun. This will add a whole mechanic shown with this image
The concept of upgrading the invented items also will change the mechanics of that item even more. As shown by these images.
Overall the grapple will attach to edges giving you the ability to swing across gaps in between the buildings. Its upgrades will consist of adding more variety to what you can grapple as well as letting you pull yourself up to the point you have grappled to. This is only summing up one one the inventions variation to the mechanics each one will develop the mechanics in a variety of ways.
Gameplay Features:
The game will have two gameplay features that will develop and get more interesting as the gameplay loops continue. these two split into the variety and complexity to the mini games that the repair jobs will add and secondly is the combinations of the inventions you can use will let you reinvent the way you traverse through the areas that you are progressively getting used to over the progression of the game.
Firstly these repair jobs you have at their core are basic and an entertaining challenge but over time as the game progresses more 'red herring' type interactions will happen within them, wires will loop round on themselves again and again. The plumbing system will reveal items that cause the timer to whittle down quicker and lastly the QTE repairs will get more complex overall making them a nice challenge to overcome throughout the game.
Secondly, the environment will be created so it can be traversed at any stage but you will be able to cut corners or find new paths through the environment with certain inventions but this doesn't stop one layer deep, if you have inventions that complement each other thy can be used together to achieve even better movement. if you grapple after having a boosted jump with the mag boots you will get enhanced momentum and it will only widen the variety of ways you can move through the urban landscape that blocks your path.