I couldn't figure out if I wanted minions with lots of HP or speed. A small damage popup when a minion is hit would be nice to have, so the player knows how much damage each enemy does. Also designing some of the levels or parts of the levels by hand should solve the RNG problem (e.g. have RNG minions spawn points, but hand placed minions on choke points). Also, I feel like the shop should always have 1 big guy and 1 fast guy available to purchase.
Anyway, the game overall is very fun to play and most of my points are small nitpicks that are pointed out in case you want to expand your idea after the jam.