I love Gemini and FOURTH which is why I have to drop this at episode 1 or I will begin to dislike them. It's not their fault but in my opinion GMMTV has dropped the ball in one way or another in every adaptation I've seen including FIND YOURSELF, F4: THAILAND, CHERRY MAGIC, OSSAN'S LOVE (which hasn't premiered yet but...) right now Im giving another adaptation from GMMTV in A LOVE SO BEAUTIFUL (I adored both Chinese and Korean versions) yet so far the Thai version is set on suck. Dew and Neo are 2 of my favorites but not even their charm and acting can save a GMMTV ADAPTATION.

Back to My Love Mix Up. Why Japan keeps allowing a place like GMMTV butcher their source material I will never know (I know it's the money)

Fourth is adorable and a good actor but I watched episode 1 and his Atom (Aoki) fell flat for me. And I can't say I blame him because the director should make sure he excels at this role. It's just not there. As for Gemini I was a little more impressed with his Kongthap (Ida) but not by much. Gemini and Fourth have a lot of chemistry but Fourth seems to be trying to hard to pull this off and as such for me their chemistry is lacking here.

I will admittedly say I did not have the privilege of reading the manga so I'm not sure if this Thai Adaptation is closer to the manga then Kieta Hatsukoi. There Aoki was more of an adorable spas yet so lovable against Ida's straight laced smart guy with no concept of what it means to like another person.
Fourth is playing Atom like he wants to be like Aoki but he's more like a slightly different version of Gun (his role in MSP)
So for me I will end with Episode 1 and go watch Kieta Hatsukoi again to show how this really should be done with Aoki, Ida, Hashimoto and Akkun (Aida) in the only version I want to remember.