The work is very interesting—I like it! Certainly, regarding the mix, you need to raise the dB quite a bit because it sounds really low: I understand it’s not mastered, but at least keep the mix between -18 dB (for good dynamics) and -6 dB FS. It’s also true that the second track reaches higher dB levels, but using a clipper (like Standard Clip, for example) would help manage excessive dynamics. Just use it cautiously, as overuse could result in the opposite effect, making it too compressed. Anyway, for a platformer game, this type of music fits really well: relaxing, with the right pauses and textures! Beyond the low volume, I think it’s a great piece of work!