-Orange companion is neat, but for what purpose does he serve?
-Moving blocks are cool, but I wish they had a unique sprite besides the stone so they can be easily distinguish. One stone was set off by the player not timed, that could also be differentiated somehow.
-Finished the demo, boss was fun. Overall, a bit on the easy side. If it was someone's first time playing, I imagine that would be good. The hardest part was with the vertical block pusher into a vertical section, that has a enemy spawner further along. This was mainly due to not having a good way to kill the enemies in the vertical section.
Good stuff, keep working on it.