This was a really fun game - and I'm a sucker for puns, so I liked the liar/lyre setup. ;) Very impressed you managed to build this in just a week!
Some comments from as I was playing through, in roughly chronological order:
I like the audio - the music on the title screen immediately set the mood/tone for the game very well, and goes very well with the game overall (it's not distracting during gameplay, while also being quite pleasant to listen to). The sound effects are also decent - I liked the falling noise when you miss a platform and drop off the screen (which, to be honest, I heard a lot - platformers aren't my strong suit!)
In terms of what I'd suggest changing: not a lot! The lyre music effect did get a little repetitive, mainly because I kept spamming it as often as I could - maybe having a couple of little randomised snippets to vary it up a little bit would be a nice touch there. Also, on my first playthrough I found it difficult to see that the fake spikes were flashing when the lyre music hit them (i.e. they are fakes), because the spike animation partly hides the flash (unless you're really looking hard for it). But that just adds additional challenge, so definitely not a showstopper! ;)
Overall, very enjoyable game, really liked the concept and the execution, would definitely recommend to others! Well done!