Overall, an enjoyable puzzle game. The graphics and overall visual style make it fun to interact with the puzzles and are just visually pleasing to watch. The way the mechanics are slowly introduced prevent it from being too frustrating.
What makes the puzzles especially engaging is how it plays as they become more complex. In some puzzle games, it just becomes an invitation to "brute force" a solution, which is not very fun and tends to be frustratingly boring. In this game, however, the puzzles each seem to have several "insights" that you can discover as you play around, which you can then use to develop a solution. The rewind mechanic makes this discovery process much easier and more pleasant - for example, if you find all of your splices used up but your result is really close to the end goal, you can rewind and keep trying different things to try to "fix" your splices until you get the answer. You can also take the approach of trying to discover useful properties about each puzzle as you experiment with different splices and exploit those properties to devise a solution.
So, not only are there multiple solutions - there's multiple, challenging and rewarding strategies you can take to discover those solutions without using brute force.
One downside is that the music seems to have only one track and is too short and played too often, however, which gets a bit annoying after awhile.
And despite beating the main game in 4 hours, I'm sure you can get a lot of additional play time out of the bonus levels (the "epilogue").