Very good game, with good mechanics, the way the magic spells changed throughout the game was a good concept, however I feel as if this could have been put to better use if:
Instead of having 4 worlds, each with their own magic spell, leading up to a boss in World 4 who you fight with World 4's abilities,
You have the same concept, but you must you each magical spell to defeat the boss. For example, tou start off fighting with the platform spell, boss gets down to 1/4 health and now your fighting with the dimension swap spell etc.
Like what TURDO below me said