Main Menu feels proper funky, and has this nice Crash Bandicoot vibe. Melody can be simplified a bit more -- I kinda feel like, in the second half, it's talking over everything else and not giving the rest of the instrumentation space to breathe.
Lousy Ol' Town, now the slow pace of it really sets the mood, a not-so-lively town. It's moody, and the melody is singable. The piano melody being in the lower register is not as overpowering, but it can be after a while. Use your rests more!
Onward has some funky time signature use which I quite like. Melody is also singable in parts. It feels like it's lacking the gravitas of LET'S GET UP AND GOOOOOOOO -- the bass feels nice and you've got the melody, but everything else behind it feels quite static and could use some movement. Listen to a Crash Bandicoot stage theme, from 4 onwards, and notice the stuff going on in the background. Not all of it is legato. It's detached in parts, very staccato, and that conveys excitement, movement. That's what we're missing here, I think.
The losing theme was, as you said, a much darker shift in tone.
Your strongest suit here is your drums and bass. I feel like you know how to make the foundations of a very good pocket -- arguably, the first step in this equation, you've nailed really well. All that remains is to build on top of it. Pocket is what gets us moving, after all -- and an adventure game where we need to be absolutely schmoovin' certainly needs it.
All the best this jam!