That's some great teamwork! The graphics, audio and gameplay complemented each other really nicely.
The background was distracting, I thought it was the green thing, but looking at it again it's more of the tiles lighting up; it makes a bit too much contrast. The color scheme is really nice, and the sprites are lovely! The spider (?) enemies were easy to distinguish from the skeletons, but their color is a bit too similar to the background. The 0s and 1s particle effects are a really nice touch! I didn't like too much how the health bars looked like?
The music is great! I love the instrumentation, but it does get a bit repetitive when one keeps playing.
While there doesn't seem to be anything too extravagant design-wise in terms of combat, it is a really nice touch how the skeletons and spiders are affected differently by the bullets. The controls feel just right! The procedural generation of levels is also quite good (is this the "hacker changing the properties of the game"? or was it something else I didn't notice?).
In any case, it looks like you make a great team! It's quite an enjoyable game you've made.