Haiyore! Nyaruko-san W

Similarities: Both involves the same pesky girl who comes into guy's life. Both pesky girls ruins guy's peaceful lives. Both involves the same comedy and harem genre. Dissimilarities: One was more of sic-fi while the other is into fantasy. One is a full 25 min long anime while the other is limited only to 12 mins. 

Both have the same romance and school genre. Both involves girl protecting guy from baddies. Both also involves girl being with the guy all the time. Both also involves girl who were strong fighters. Dissimilarities: One anime has a brocon element, while the other has a yaoi element couple with oedipus complex from the guy's mom. The guy in one anime is very comfortable being around the girl, while in the other anime the guy isn't getting enough space from the girl. One anime has comedy as it extra genre, while the other has action and magic as its extra genre. 

Motto is the second season of To-LOVE-ru. The first seasons were extremely similar, and so are the second seasons. Both contain bad guys that are not exactly evil and have wacky gadgets that can do seemingly anything. And most importantly, they are both about an alien girl forcing her way into the love life of a human boy.  

While there may not be any direct similarities, the shows emit very similar feelings. In addition, they both have somewhat similar art styles, and are very upbeat overall. 

How to start a season 2??? These both do it wonderfully. In just the first episodes, the series ideas and background (as well as basic idea of what happened in season 1) are explained in a unique fashion that makes it entertaining for the returning viewer and informational enough of the new one I recommend watching season 1 of each first, but check them out 

Nyaruko-san and Seto are both revolve around mythological girls (Cthulhu and Mermaids) and ordinary male MCs. The second season of Nyaruko-san (W) is particularly intense in parodies which is also a central theme of Seto. 

Both involve fantasy elements in the human world, have slight romance and action. Hataraku has much more detailed and "important" action scenes though. 

Both are hilarious anime that use outrageous situations to make witty jokes; they don't break the fourth wall, they disintegrate it! Both of them parody other anime. Many of the characters in both series have a habit of simply blurting out whatever is on the edge of their tongues. I'm pretty sure that you'll like one if you liked the other. 

Biting parody; coyly subverting shounen and harem tropes and then joining in the fun. On top of that, the generous amount of fanservice is enhanced by the lovely character designs. 

Both shows have interesting pop, Japanese and Western, culture references.  

Both are VERY funny, have a lot of other shows factors in it: like Dragon Ball, Doraemon, One Piece etc. There is a pervert(s) too.  

So here's how the two are similar: - Both shows have aliens in them. (Nyaruko and Lala Satalin Deviluke) - Both shows have male characters who are somewhat tsundere-like to the female character. - Both shows are hilarious. (Although I like "Haiyore! Nyaruko-san W" more) - Both shows are somewhat ecchi-like. (Actually To Love-Ru is ecchi) If you love to laugh a lot, then you're gonna love "Haiyore! Nyaruko-san W" or the prequel "Haiyore! Nyaruko-san."