Ikki's route is played much the way Orion's opening dialogue leads you to expect. The protagonist wakes up at home with no memory and does her best to hide it from those around her. She doesn't always succeed to the degree that she'd like, but the dialogue options offer some creative ways to avoid answering questions.
While Ikki's route has a level of mystery about it due to the player's amnesia, it doesn't quite manage the oomph of Shin or Toma's. This is largely due to the fact the plot doesn't seem to have much in the way of suspense beyond the fact she has amnesia in the first place. Sure, the player and the protagonist have a lot of questions, but Ikki's route doesn't feel like it has a problem beyond what recovering the protagonist's memories would solve.
His route is largely a story about a good looking young man with the unfortunate ability to charm any woman who meets his eyes. In other words, his story is more about him than the relationship between him and the protagonist, and I never quite got the feeling that Ikki loved the protagonist for herself rather than simply being the only person who can resist him.
Ikki cannot have a normal relationship with someone who is constantly under his sway due to his "condition" and he's annoyed by that. By the time we meet him he's been like this for several years, rotating girlfriends and figuring even if he can't find anyone he likes he might as well have a little fun.
His condition is a little weird though, in that other than Orion and the protagonist's magically induced amnesia, supernatural elements are sparse from storyline to storyline. But there is no doubt that Ikki's condition is supernatural given the way it works. Shortly after eye contact is broken, women come to their senses.
The protagonist is the only exception, and he's both intrigued and a little disappointed that his eyes don't work on her.
As with Shin, the protagonist starts out already dating Ikki, but despite the fact he's the playboy character, he hasn't actually gotten very far with her. Most of the mystery is figuring why the protagonist is going out with him in the first place, why she puts up with all the crazy girls in his fan club (especially since they're constantly trying to drag him away from her), and what is this mysterious deadline where he wants her to fall in love with him by the end of the month.
While interesting, it's just not as compelling, because it doesn't feel like there's a greater truth to be found. With Shin and Toma there was a lot of "Do I trust what they're doing?" and "What is the real story?" But with Ikki, the real story is pretty much what you see.
Ikki has girl problems. Ikki likes the protagonist even though he has to sneak around to see her. Eventually, Ikki develops a spine and girl problems end.
The protagonist actually does very little other than get jealous and a little upset at Ikki to finish off the storyline. The most engaging parts of her involvement are early ones when she's trying to get a hold of her situation, but after that the show is all Ikki's, and arguably if Ikki had more backbone there wouldn't have been much of a story at all.
The thing is, despite his confidant playboy image, Ikki is actually a doormat and a people pleaser. He can't stand being mean to girls who can't help falling in love with him, and while that's an admirable trait, he's not good at drawing the line between being civil and explaining that he really can't keep them company, which results in Ikki constantly being late to dates with the protagonist and running a charade that he actually doesn't care about her.
Some of the stuff Ikki and the protagonist arranged pre-memory loss was just flat out nuts to accommodate his desire to be nice to everybody. For instance, he wants to walk home with her from work everyday, but he gets mobbed by his fan club so he always meets her about a block away after he manages to humor them.
It's not like he's trying to be a gentleman about it. He ignores her when she leaves, even though she's known to be his girlfriend, and escorts one of his fangirls to the train station before turning around and meeting up with the protagonist. He does this to avoid upsetting his fans (who would otherwise bully her) while still sneaking around to see the girl he actually likes, and the pre-amnesia protagonist knew that this would be their mode of operation, even though she didn't particularly enjoy it.
But the story can't end with that as a permanent arrangement, especially since the unwritten rule is that Ikki never dates anyone more than three months and the end of August is the deadline, so in the good ending Ikki confronts the fangirls openly about who he likes and that they better not do anything to her or he won't have anything to do with them.
In the middle, there's just a lot of waffling back on forth on Ikki's part, trying to please his fangirls while trying to keep them from bullying the protagonist, and trying to get the protagonist to fall in love with him, when there's really no compromise. The ramp up to what might be considered the climax is actually Ikki suggesting they should take a break from their relationship, with the difference between one of the bad endings and the good/normal endings is whether or not the protagonist is jealous enough to confront him about it.
Yes, he's willing to walk away and give up on the girl he loves because he can't say no to other people.
I mean, it's not that he's a bad character, Ikki himself is sympathetic if flawed, but because all the problems encountered were easily solvable if he would just make his wishes clear, his story didn't carry much weight with me, and I never felt like I got a good feeling for what Ikki and the protagonist's pre-amnesia relationship was like.
But I will say that if one's personal tastes run towards a romantically tormented love interest, Ikki's voice actor does a wonderful job conveying how messed up he feels inside. Ikki's desperation for the protagonist's affection is clear, even if the reasons for his desire are not.
Oh yeah, not critical to the plot in any way, but this is the first otome game where I have been drunk called by a love interest. Not make or break in any way, but Ikki being heavily inebriated was a good laugh.