Glad you enjoyed the game!
Balance is certainly way off at the moment, there's really no "easy" enemy if you get bad luck. I might do something along the lines of making easier enemies spawn closer to the entrance. Free item per level might be an unlockable thing once I get around to implementing a meta upgrade/unlock system.
The boss does make yellow builds worse, but I intend on having multiple boss options per floor/level so he won't always be there to ruin your day. Even then he might need a nerf honestly, maybe his Greed should be a timed buff that he has to give himself.
Tourist is meant to give you useless symbols because he is otherwise harmless. It's a "time limit" kind of enemy.