Hey!
Thanks for playing; I'm glad you enjoyed it :D
In the last update, there was actually a bug that made the waves easier after a certain point (oops)
A lot of people have requested mixing weapons to upgrade them. I do plan on adding a way to upgrade weapons, but currently I'm focusing on game balance.
I'm also slowly but surely adding more enemies. I just added another elite, and I'm working on some new normal enemies.
Thanks again for your support; it's really motivating! :)