First things first
I feel that it is important to prioritize properly. The first things I concentrated on were basic action rpg elements, a stats system, health, combat, and movement. I really focused on polishing these fundamental aspects of the game and feel that everyone should at least have these mechanics down.
After polishing these mechanics, I was able to start getting creative. I added a "special" attack system and a way to charge that special attack up. It was also at this point that I started to think about the minions and what part they'd have in this game. I'm still on the fence about using a spawner, but I have another idea in making a different character that the player could choose who would be able to spawn minions to fight for them.