Sub Sonar is a very polished and well-presented jam submission. I really enjoyed the transmission-style opening: it gives the game a strong visual-novel briefing feel and immediately makes the Bermuda Triangle setting feel more interesting. The animated main menu, glowing effects, and overall UI presentation are excellent as well.
The core loop is simple and direct in a good way: monitoring the sonar, deciding what to prioritize, managing resources, and defending the base creates a tense underwater strategy experience. I also liked the idea that not every contact can be trusted, which makes the sonar theme feel fitting for the jam.
My main suggestion would be to improve the readability of a few small text elements, especially at the resolution used on the itch.io page. Fullscreen makes them easier to read, but slightly larger text or stronger contrast would help the game communicate its information more clearly from the start. I also noticed a few minor UI consistency details, such as buttons whose top border does not match the surrounding frame; using transparent icon buttons there could make the interface feel even more cohesive.
Overall, this is a very nice build with great presentation, a strong atmosphere, and an interesting defense concept. Great work!