There's nostalgic charm if you're a fan of the films of this era. I happen to hugely admire the Ivan Tors film and TV projects. This is possibly a script from the 1950s, as it was co-written by actor Richard Carlson, who made SF films with Tors in the 1950s. It's certainly creaky stuff that seems outdated even by the mid-1960s when it was made. It's far more a fantasy than the usual Tors material, which strove for believability and achieved it. This doesn't. The animal sequences, which were always top-notch in Tors films thanks to trainer Ralph Helfer (inventor of affection training), but here they are awkwardly shot and silly. The cast is likable but the script is just not up to making anything work to its advantage.