Mercenary mode is a new thing that I'm adding to Silas. It is basically comprised of a bunch of missions in which you can gain different scores in. You progress through a series of levels and worlds. Below you can see how this is setup in the menu:
You can earn up to 100 credits in each mission! So basically I choose this over a 5 star rating scale and the such since it is more dynamic. The better you do in the mission and the quicker you get it done the more credits you will earn.
Your total credits can then be posted in an online leaderboard I will be making soon. So you can see how well you compare to others. At the end of each world there is a boss battle or sorts. Once you unlock a mission, the next one is made available.
In this screenshot you can see the first mission which is really easy. It's basically fetch 5 Item Cells before the time runs out. I just put this in tonight.
If you have any ideas for future missions let me know! I want to make the difficulty escalate with each world. The cool thing about Silas is that there are many weapons to choose from, so in some missions you will kill creatures. In others you can fly around, ect.