I like the chords and the melody here a lot, and I feel for this kind of chiptune the drums are driving and well done. I did notice that the bass seems to be pulling everything in a different direction, though. With the intro it felt like the song was going to be in a minor key which might be a little more fitting for a tense gym battle. The melody and chords on top of the ostinato seem to be in a major key and sound happy while the bass is trying to be minor and tense, so it's hard to pin down what your intention was. Keeping the ostinato the same can be effective but I would try to nail down what key you want to be in and you can find chords that would fit the bass part without it being too crunchy.