Spooky music brings out the environment a lot, could have used some soundeffects though.
It took me time to figure out how to push back the pyramid and which area/angle to shoot the pyramid at. One thing I will say is once I knew the game I didn't really feel the need to continue. There was no reward or anything new for pushing the pyramid back. It was just keep playing until the pyramid inevitably falls and you have no more projectiles.. There needs to be some feedback, an incentive to keep playing.
Other than that is was an ok game. Really could use some polish though.