Since the Real Career Mode is under development, I made this. My own very Simple Career Mode. Where you can challenge yourself and get rewarded. Purchase tech and own it. You can contribute and challenge other players by adding or changing the list of missions and the sequence of tech trees.
Here's how my Career Mode works:

This workbook contains 3 worksheets: Ledger, Missions, Tech Tree.

Ledger

Missions

Tech Tree

How to Do Missions

After Mission Success

Add 'y' for Yes to gain the reward.

How to Purchased Technologies

Go to Tech Tree

Download the Career Mode Excel here.