Milestone 3 is done!
For this devlog, I will share the basic gameplay loop in practice. First of, let us look in the shipyard:

It's very empty, since we haven't played yet we haven't discovered any upgrades. In lore, we haven't even tried our submarine yet, so we don't know what we want. Let us head out on a quick patrol.

Get spotted idiot, we now have 1 Reputation for spotting this transport ship. Let me head back to dock.

I have now discovered a possible upgrade, since I reached the Reputation requirement (a whole 1 Reputation). Let me enqueue it.

Now I need to head out on patrol, and my engineer will think really hard on how to achieve this upgrade. For this upgrade, I need to be on patrol for a whole 5 seconds for it to become unlocked. Let me go on a quick patrol...

There we go, let me install it and head out on a final patrol!

And there she is, the small engine.
Note that all UI, values, graphics, etc, are work in progress. I have only achieved Milestone 3 / 5 for my MVP, i.e. the absolute minimum viable product. The final MVP will more be a tech demo, having the core loop, but not much more.