Did you work in a team?
I did all the production work myself in my mornings and evenings before and after my day job, but I did take my ideas to some others whom I have listed in the credits for advice.

If I had a team I may have been able to expand the scope of the battles involved (eg. perhaps having a "campaign" or story mode of sorts?), but I started the jam 5 days late because I wasn't sure if I would have sufficient time and energy to finish it and therefore never asked for someone to commit time and energy of their own to it. I also didn't use an engine, which meant that my content pipeline support was pretty much non-existent (which is why the assets are all raw .BMPs and .WAVs instead of something more optimal like a compressed archive), and that would have made integrating other content creators a bit more challenging.

In spite of working solo, I also never worked past my bedtime (unlike on some past jams), which I think was very good for the quality of my entry as my sleep deprivation wasn't any higher than it usually is.

Was the resolution a challenge?
I consciously chose a game idea that wouldn't require a ton of art, since I didn't have a ton of faith in my drawing abilities at any scale. Most gameplay elements on the plotter screen are just pixels and this is by design; even at a higher resolution they wouldn't be much more than that. I wanted to focus on the ship simulation and the verbs the player had access to. I think this was a very good choice - most of my time wasn't spent on art assets, it was spent on adding game mechanics! The audio cues do some of the lifting in the "suspension of disbelief" department, too.

All that being said, I had less trouble with the pixel art for the cinematics than I expected and I'm pretty satisfied with how those turned out, but much more trouble with the HUD icons and user interface in general. Most of the issues came from the fact that this kind of simulation tends to be quite information rich. There's a lot of stuff the player should know about and I ended up junking several game mechanics that I started implementing and then realized that I could never fit in the UI.

At one point part I figured out that the resolution constraints basically demanded a non-diegetic interface with tiny icons, even though that isn't standard for the naval sim genre at all. I had to fight the impulse to add more text and buttons and lightbulbs for pretty much the entire time I was working on the user interface. 8x8 pixels also turns out to be tiny for an icon and there just isn't room on a 64x64 for all the information I wanted to present. Too much information, not enough pixels.

That also meant putting together a tutorial was a huge challenge. The one I put in just explains what the most essential controls do, which is all I really had the space for. The rest of the context of the game is therefore explained - in the style of one of those old game manuals that used to ship in the physical boxes with games! - on the game page, so I highly advise going there to read about some of the mechanics. I just didn't have the space to explain it anywhere else.

I'm pretty pleased with the UI I built overall, even if it went against my instincts a bit. I'm also pleased with how the gameplay mechanics turned out with the simplicity enforced upon them and how much that caused me to focus.

What did you learn?
This was the first time I've used test-driven development in a game jam and it worked out better than I was expecting, even if I didn't do it for the entire game and I kind of stopped doing it once I had some actual gameplay running. The nice thing about it was that it let me iterate on the gameplay simulation quickly and without needing art assets in place. A common misconception is that TDD is about code correctness and it's not, it's about productivity, and my experience on this jam affirmed that to me.

Since this game takes place in a historical setting, I initially felt a drive to conform to the facts I know about what went on and what technology the Allies and Axis had, etc. - the escort on the title screen is meant to look like a Flower-class corvette (as much as I could given how few pixels I had, anyway) and the u-boat is I think obviously a Type VII. Once I started on the gameplay and realized how little information I would be able to show to the player I figured I had to simplify a lot of things - no separate chart table and sonar scope, for instance. I had to learn to sacrifice historical accuracy to a very great deal to fit in the time and resolution constraints.