There isn't a lot more to it than that: you end up causing the spell switch, and the whole thing's over in 15 moves. It's not flawless--it's possible to render the main puzzle unsolvable by doing things in the wrong order-- but there's not much wrong with it, either. The main appeal of the game is in the humor: there are Infocom references sprinkled here and there, and the wonder-what-happens-if-I-try-this results are suitably amusing. There isn't really enough here to call this a full-blown homage, but it's enough to capture the feel.
Perilous Magic is a short but reasonably entertaining effort that suggests that IF authors and players have ridiculously good memories for throwaway jokes in manuals published in 1984. As a game, it's nothing special, but it's not a bad way to spend five minutes.