Disclaimer 1: I plan to rewatch this anime later so this review may change. Also, I watched this anime when I was 13/14 years old and later (18 years old) played it's otome game in steam ( this game is so cheap on discount! Give it a chance after you read this review).
Disclaimer 2: In my profile I gave this anime a 5 stars but that's more personal opinion. I tried to be more realist here.
This anime is based on a very popular otome game (visual novel and dating sim targeted at young girls) so you can already expect it's story will be good.
On the first episode we get to know Orion and the heroine/MC (Main character). The heroine lost all of her memories because Orion, a spirit, possessed her. Thus, Oion tells her that for him to leave her side she needs to recover her memories through stimulation, like going to previous visited places and talking to friends.
Then, her journey begins as she gets to know every hot guy character who claims to be her boyfriend. Through the whole anime she will travel amongst different timelines and worlds. I'll stop here as I don't want to give you more spoilers.
Stay for the last episodes (or last "route") as this will explain the whole plot better and is what made this game popular.
This was low budget right? At the time I didn't notice THAT MANY animation mistakes but now... Character design is good but the animation didn't help (this is a problem in many otome based anime). Nevertheless, the coorful colors made it a little better.
The game HAD GORGEOUS OST, so obviously the anime also has it. The op (ZOETROPE) and it's ending are specially good. Ukyo's theme go specially well with the anime as it appears at suspense scenes.
This is it's strongest point! Every guy character is different and has a different story. You'll end up crying at the last episodes for the last character though. Nevertheless Ken't route (the guy with glasses) was badly adapted in this anime.
The heroine doesn't have personality. Well of course she is the MC so it is supposed to be you, that's why she doesn't talk.
Also, you may not like this anime because of Toma. Many people critque him for it's toxic relationship. But it's still interesting so...
The story itself is too good. You can also experience it through this anime, though, the animation may be problem for many of you. I actually recommend you to play the game: Amnesia Memories, rather than watch the anime but not many of you may be willing to pay for it (even though it's just 2 dollars on discount which is almost always).
If you don't like guys I don't know if you'll like this as this is more fanservice for girls. (Don't get me wrong the guys are hot but it's not like Free which is PURE FANSERVICE).