It used to be easier, but I buffed the enemy spawn rate last minute to make it a little more interesting(you'd spend much of the start of the game just waiting for enemies to spawn/kiting a single enemy if you were to shoot them straight away, which didn't seem very engaging).
I think in retrospect, I should have chosen a spawnrate somewhere inbetween, and made the spawn rate ramp up slower.
Glad you liked it though!