This game is hard but it is fun to keep going after that next upgrade to see what you might get! I think randomized upgrades can be a lot of fun for that reason.
My first time I got to round 17 and my third playthrough I got to round 39. The strategy I used there was to throw everything I could onto the swordfish. It worked alright, although I think part of my undoing may have been the "+10 health, but lose health over time" upgrade...
I do think something I would really like to see would be, like, health bars or some kind of indicator like that... it's not very easy for me to understand exactly how the combat works as it stands.
But, it's definitely a fun game, and I may give it a few more tries at some point here. 😄