This is a nice little prototype of a beat-em-up game. There are some interesting ideas, such as the ability to slow down time, but the whole thing just seems a little "off" to me. It is a prototype, so it's to be expected.
One thing that stands out to me is the ranged attack: I initially thought it was underpowered because it takes so many hits to defeat an enemy, but after playing a while I discovered that even so, the ideal strategy is to just run around until all of the enemies are in a group and then hit them with the ranged attack until they die. Some balancing needs to be done there for sure; maybe make the ranged attack stronger but more limited in use, say only if you get a certain item drop or after you've earned power from melee attacks?
There also needs to be something interesting to bridge the battle segments, be it a cutscene or a minigame. As it is now, I want to dash between the areas, but it doesn't work well for that purpose.
I also feel it necessary to comment on the fourth wave being wholly unnecessary unless you're going to add new enemy types/behaviors to the mix, and the boss needs some work as well. On the topic of the boss, having her offscreen so she cannot be hit really slows things down in an unpleasant way. I suggest reducing the boss to one mechanic, either making dodging the offscreen shots the main mechanic and then allow the player to get some hits in after she's exhausted, or just have the parry/attack pattern.
Needing the mouse only to advance text was clunky. I hope you can make that a keyboard key in the future (and perhaps point out which key needs to be pressed if it's relegated to a single key).
Now for some positives: the attack range is wide enough that I felt like my hits connected when they were supposed to, the limited energy meant I had to use at least a little patience and strategy when employing my long-range attack strategy, and enemies are predictable and defeated in a reasonable number of attacks (you still might want to reduce their health a little). There's plenty of contrast between the characters and the background, and could always tell where my character was (except for a few points where a traffic signal post in the fourth wave would get in the way and obscure my view).
I wish you the best of luck as you continue to grow and improve this game!