The SFX are good, but just some music would really improve the game. Its nice to try new tower setups, which is a must for a tower defense, but is not very intuitive where are the best spots. Overall a really good game.
Yeah I agree, I really wanted to add music. I actually did create some but I ended up scrapping it as it was really bad (it was my first time making music)
You could just use some royal-free music. But the purpose of the game jam, is to try things, if you had put your music, someone could help you improve ;)