Unsuccessful half the time, but it's quite interesting to look at why.
Firstly, what are these? They're ONAs (Original Net Animation) each of which is about six or seven minutes long, but that includes three minutes of opening and closing titles. Amazing. Anyway, what we have here is three weak episodes, followed by three funny ones.
Rikka tries to play... oh, you guessed. Her eyepatch kills her depth perception, but she refuses to take it off. Yuuta helps her practice. It's not a bad episode, but it's as throwaway as you'd expect and it could have done with a stronger ending. It feels a bit like a cut scene.
2. The Dawn of the Wicked Eye
The origin story of Rikka's eye patch. The episode's okay, but it's fairly bland and again struggles to feel as if it has a point.
3. My Older Brother
Yuuta's younger sister (Kuzuha) narrates a story from the days when Yuuta was also a full-blown chuunibyou. Not as funny as you'd think.
4. We'll Make Meat and Potato Stew!
(It's called nikujaga, by the way. It's nice.)
This is the first episode that's actually good, I think. Yuuta's youngest sister (Yumeha) asks Rikka to help her cook dinner. Not a good plan. Rikka's domestic skills are... not the best. What's funny about this episode is Yumeha's unshakeable faith in Rikka and wide-eyed acceptance of everything she says. Well, she's five. She'll learn.
Ironically they don't get around to cooking and the episode doesn't even get a sequel. They return from the shops just in time for the closing credits. We also get some amusing Rikka-vision.
5. The Sleeping After School Beauty
Another good episode, this time a Kumin-centric one. Admittedly it's hard to imagine a full-length episode devoted to someone so easy-going and marshmallow-like. Her favourite activity is going to sleep and she'll tend to have done so within five minutes of arriving anywhere. However she has a distinctive worldview and it's both amusing and interesting to see the world through her eyes for these few minutes. (She's also arguably the most perceptive cast member, not infrequently noticing things about people that they haven't even realised themselves.)
It's set in the club's meeting room, or as Kumin sees it, Napping Central. Eventually all the gang shows up, which is fun in itself.
6. Dekomori vs. Nibutani
Two friend-emies, one a pigtailed lunatic and the other trying to maintain a public facade of normality. A silly war. Lots of entertainment.
The main thing these episodes teach us is the value of foils. Every comic needs a straight man, or at least that seems true with these lunatics. Rikka being deranged in ep.4 has some inherent humour, for example, but the comedy wouldn't be half as effective without Yumeha. Going through some of the other foils...
Yuuta is the natural straight man for Rikka, but ep.1 is fairly low-key. Nibutani-Dekomori in ep.5 and especially ep.6 are far more explosive, because of how much they wind each other up. A particularly interesting one is in ep.2, though, which is set before Yuuta and Shinka had transferred to this school and hence is severely restricted in its available cast. Does it use Touka? No. She'd have been fantastic, but no. Instead we meet Tomo-chan, a sarcastic girl I don't think we've seen anywhere else. She's not bad, e.g. her deliberate refusal to read between the lines of what Rikka wants her to do, but at the end of the day she's a snarky footnote who only exists on-screen for three minutes.
Meanwhile Yuuta's sisters can both be excellent foils, but Kuzuha isn't well served here. She's funnier in the TV series. That said, though, ep.5 is great in ways that have nothing to do with comedy foils.
Overall, a very mixed bag. Some of these are the only episodes of Love, Chunibyo & Other Delusions that I think don't work. Others are lots of fun. I also appreciated getting "day in the limelight" episodes, in which minor characters like Kuzuha and Kumin are allowed to become the narrators and main characters. Needed more Touka, though. I'm happy I've seen them and at only three or four minutes long (excluding the title sequences) they won't take great chunks out of your life, but this very brief series is halfway through before it gets going.