Nice short game, got some references you threw in there too (love Steins Gate).
I noticed that changing scene back to the original one restarts the main music theme, without stopping the previously started one though, so you end up having multiple overlapped themes that play together...
I still enjoyed the game though, especially liked the pixel art and the music!
If you can, you should also add other interactions between item in the inventory and items in the scene to make it even more fun :D