The third and likely final update v1.6 brings with it:

• Many different sound effects have been added
• All major bugs except for two have been fixed, remaining ones are lvl 2 can get a walking sound stuck in the background sometimes. Final score doesn't multiply time left and add to the total score. 
• Bosses have been improved further, and visual and sound effects have been improved.
• WebGL on mobile has an issue playing the loading scenes so some content won't display, I'd recommend playing Android for mobile if possible. Works well for PC.