Photon

You will have almost the same feeling from both these animes. IF you enjoyed one, Im sure you will enjoy the other one as well. How ever OS has almost no ecchi scenes and low humor, however I guess the Effect is almost the same.  

Humor focused though different types. Post apocalyptic. Same color for practically all characters even if the characters themselves are very different. Except maybe green.  

don't know why, but have similar feelings during watching. Both series looks like not really serious at the start, but they are rather serious, I think. About strange people, their journey for goal and adventures during this. But Kaiba is more interesting for me. 

Same creator. Similar perversions. Similar comedy types though photon's are closer together. 

In tone, atmosphere, art, type of humour and general zaniness, "Photon" and "Labyrinth of Flames" strongly resemble each other. While the former has a more developed story (due to longer runtime) than the latter, they both feature well-paced action sequences and a limited yet interesting array of strongly individual and more often than not ridiculous and obsessed characters, all the while being really fun rides through somewhat outrageous comedic situations with a dint of romance... and loads of proper fanservice! "Photon" and "Labyrinth of Flames" don't take themselves seriously at all: you're in for pure, wacky comedy provided by over-the-top behaviours, where the story is put on the back burner and is essentially an excuse for playing heavily and tastefully with clichés (albeit more subtly in "Photon"). read more 

These two 6 episode 90's OVAs show very different adventures, but both have a similar character dynamic where two main characters compete to see who would be the better 'wife' for the titular male character. 

Alternate/related versions of their more well known counterparts (Tenchi Muyo and Saber Marionette J). Expect harem dynamics with a 90s attitude, good looking action and an atmosphere that goes from happy-go-lucky to complete dismal.  

Harem around MC-idiot + light space adventures 

I can honestly see a lot of parallels between the characters Photon and Totoro. Photon the show is cute, funny, entertaining and criminally under-rated. The series is only 6 episodes long, and suffers a pseudo-plot bomb in the last episode (which is twice as long as normal), but that doesn't make it bad, it just feels a bit rushed at the end. Overall, it's only 6 epis, you're the kind of person with a myanimelist account. You can spare the time to partake in Photon. 

Crazy, out there, and upside down. Both of these series exhibit an older style, one not typically seen anymore, but the humor is corny, crazy, and out there. And yes, one is fantasy, one is sci-fi, but that doesn't make them any less out there and wacky. That's about as far as I can go without spoilers. 

The main protagonists are of the same age, yet also find themselves getting into trouble simply because they're different from everyone else on the planet on top of having friends who also find ways of getting them into trouble. The styles are rather similar, which isn't so surprising given that they are both older series. Neither know what they're in for let alone what they will discover by the end of the journey. 

This animes are VERY similar. Both had space pirates, galactic government, in love princess, super powers, funny situations.... And the character of the both anime was design by Masaki Kajishima.  

Both have similar feel with - => kind of dumb MC => Harem of girls who fall for the MC => Incredibly sexy girls => Photon has better comedy than 1+2 

Being made by the same creator, both have many similarities, such as the harem and childish yet ridiculously powerful male lead. 

From the same Creator (Masaki, Kajishima) and the Tenchi Series. The Comedy is the same, like the other series that Masaki created. It's definitely good to relax. Also if you have ever watched Evangelion or/and a Tenchi Muyo anime than you'll like Dual Parallel! Trouble Adventures, as it's a parody of Evangelion in Tenchi Muyo or rather Masaki Style. 

if you like randomness, action, comedy, drama, sci-fi......well, if you liked Photon, then you will be blown away by FLCL