Yeah I understand what you mean but the whole game is designed around the idea of having the enemies move at different speeds, a lot of the work these days has been in setting up a system that calculated their required time to reach the player and determine the time when the needed to spawn all depending on a random speed the system assigned them. In previous tests, having them all move at set speeds made the game incredibly dull and predictable. Also, the theme of the jam is "A Lot of" so I wanted there to be many enemies on screen to give the impression that you´re facing a ton of enemies and not just independet streams of 1 or 2 at a time. If you managed to activate the special, it´s this very concept in its´ more raw form.
What I´m trying to say is that I value your feedback a lot and sorry if it looked like I dismissed your suggestions too quickly, I completely agree with your complaints but I think that the solution should take a different shape to mesh with the main design ideas behind the game and not change it too much into something else.
I think that in the end I may have set the maximum speed too high and also I should´ve made it so that faster enemies should have some kind of priority and be drawn on top of the others to maximize their visibility. This is also why I said that I should´ve given them more distinct sprites, I tried doing so but it was very difficult with a size of 16x16px and a very limited color palette . Also, I should´ve made it so that the enemies reached the player in more extreme positions (high or low) instead of in intermediate ones, that only adds up to the mess.
If you don´t agree with anything I said please don´t hold back, your comment has made me think about this issue a lot and consider new ways to improve the game, so thanks a lot for your feedback!