This is a really impressive game to have made in just four days, and it's got quite a bit of juice and polish to it too! I loved the rising pitch when you selected actions. You had great visual feedback for damage with the particle effects and flashing red as well.
One small change I would do to add even a little more variety is add some randomness to the frequent sound effects like punching, lasers, and taking damage. When a common action is going to be repeated often, I try to have 2 or 3 different variations of the effect play at random or else it gets tiring to the player's ear. However even if you only have one sound effect a nice trick to increase variety is to slightly modify the pitch by a random amount. I like to start at .95 - 1.05 of the pitch and see how that feels for the particular effect and adjust from there. The slight variation helps the player not notice it's the same one or few sounds over and over again and makes the game feel a lot better even if they don't notice it consciously. Since you're using unreal, this is what my typical sound effect cue looks like if I'm using Unreal's native sound implementation. A random select node to pick from however many SFXs you have, and then the modulator node to randomize the pitch and volume slightly. Just this small change pays massive dividends!
Awesome job!