One of the known issues is that the game keeps playing after victory. Well, I made it to the last door and during the cutscene, my crystal kept getting attacked. This led to me first getting a Victory screen and then soon after getting a "Your crystal has been destroyed, try building more turrets" screen.

Not sure if this is intentional since it's in alpha and there's nothing after the final door or what. Just wanted to throw this out there just in case.