Thank you, having a game that's enjoyable to play is really good news for us!
We too would have liked to take the game further and add more depth, difficulty, and juice.
Thanks for playing and for your feedback!
Yes, we ran out of time to do more than lay the foundations. The goal is to have several different enemies with different characteristics, as well as different weapons and the ability to buy/upgrade them and add polish (sound effects, juice, animations).
The Godot icons that appear in the upgrades are a good example of our lack of time, because everything works, but we just don't have the images yet.