That's a really good idea of having some enemies that require a bit more coordination to kill with like what you said about having to hit them at the same time on two different screens. That is for sure something I will experiment with!
I've tried making a fair amount of changes to prevent people from feeling the best way of playing is just spamming and running around, this is something I certainly need to tweak a bunch till I can get it to feel right. I thought having the 1.5x damage multiplier you get for not attacking for 2 seconds would be enough but it was not. Originally there were going to be much more advanced weapons stats with ranged weapons, slow but high damage weapons, and fast but low damage weapons, however, I didn't have time to implement this. Perhaps once I do implement it then this issue will be resolved.
I'm glad to hear that the armor being tied to the weapon worked so well. I wanted to make players make tough choices like you said you did where they would need to chose some higher armor or higher damage which risks dying. The coins were actually added for the express purpose of forcing the player to have to actually move around the level rather than standing in once place so really good to hear that was working.