The best thing about the game: Visuals and soundtrack. Both meet very high standards in most areas.
Everything else is proved to be an underwhelming experience.
You go about killing some "mini bosses" to unlock doors for bosses. If the idea of mini bosses excites you don't get your hopes up too fast. They have one attack pattern, are easily killed, although sometimes you must kill them without weaponry.
When you get them to low hp, a mini game starts. The mini games have a lot of variety which ranges from tapping one key, catching falling stars, to tapping several keys at the same time, all placed in an awkward position (e.g. x+v+spacebar+e). The mini game you are given decides what will be the killing animation, which are all silly. What they do have in common is that they get boring quickly and can't be skipped. Some minigames have a timer so if you are not quick enough to read the instructions you will lose the minigame and actually take damage, potentially killing you which is highly annoying.
The platforming itself is mundane at best and worst, although you do get to fly with a spaceship, pilot an aircraft and drive a submarine. But even those things didn't offer a big enough relief from the overall boredom I was feeling. The most annoying thing in the game happens when you get hit: Similarly to oldies like Ninja Gaiden, you get knockbacked when you get hit. The damage immunity after the hit doesn't last long enough, so it is possible that the enemies play ping pong with you, you get knocked back into instant death spikes, or lose half of your hp because you got knockbacked into a wide boss and can't escape without getting hit a few more times.
If the beautiful background and fitting music is enough for you, by all means, this game has one of the the best I've seen. If you, however, care about gameplay more, you can safely skip this one.