Well, the two tracks are nice. In fact, they could be the background tracks for two different stages of the same area.
The second (boss) track doesn't sound like a boss track. The instrument for the melody should at least be different than the first track, possibly a Siren and/or a guitar.
Also, you should use a different style for the melody. It sounds like you are using the same technique of running up and down the scale (using similar scale sequencing techniques). Try using a different scale (maybe a pentatonic) or some chromatic licks. Also experiment with wider distances between the notes besides relatively close, perhaps a circle of fifths or arpeggio distances (like going down the scale with the notes of one chord and coming back up on the notes of another ).
Finally, experiment with melody syncopation for the Boss. It adds a little stress. Lead out with silence and a siren, then fade into the boss music, like Sonic the Hedgehog.