I had to play this game by myself because I have no friends and any girl would probably find it as an obvious and awkward hint if I tried to convince them to play this with me. However, this game did ease my lonely soul.
If the background music to this game was what I woke up to every morning, my life might be pretty easy. So first off, good job picking a song that matched the game's theme and length perfectly. Also, as cheap as the physics and movement might seem to some, it plays perfectly. It's not overly thought or glitchy. In fact, it's just humorous enough to have two people bumping into each other (I like to complete a level during a jump) that it also matches the upbeat, carefree vibe of the theme song.
You have a knack for level design. The last level was the only one I had to restart, but my mind felt active and engaged during every level. No solution was entirely obvious because you don't denote exactly what any triggers will perform. I know some people prefer to eyeball levels and solve the entire level before starting play, but so long as the evolution of a level relatively pain-free, I don't mind either way.
I'll give an example of another game - Pixelo - which you can find here on Newgrounds. Mathematically, every level could be solved if you could think enough moves ahead... It's really a game about truthy or falsy matrices. However, in practice it's difficult to see that many moves ahead. The more you play the game, the better you get at proving single moves are correct, rather than trying to solve the entire board at once. (Unless you're just that good. I don't know.)
Anyways, a gripe I actually had about Pixelo is that it punishes you for making bad moves. I don't believe in punishing players too harshly.
Thankfully, your levels are small, challenging, and at the same time very fluent. If you make a mistake, you can generally go back and fix it. I suppose you have to assume your partner is somewhat competent and isn't just going to stay in the same place and get locked inside of a wall... but I didn't find it to be a major issue.
I would say go for more intricate levels. Increasing game length is a difficult thing to do. And if you have too many levels with basic play, it gets very frustrating to players. Examples I'll cite are Super Mario Bros. 3 for the NES and Kid Chameleon for the Sega Genesis. Kid Chameleon especially had many levels as the game went on that felt like procedurally generated variations of previous levels. It got annoying. After playing so many levels, you felt as though you should have already been rewarded for mastering the "level type".
That's an issue I foresee if you had spent time creating more levels. I'd ask myself, why am I still being presented with challenges, even though I've proven myself capable of completing them?
Obviously, you could have added things like teleporters, lasers, enemies, etc. I'm going to be honest, the fundamental idea behind these type of flip-the-switch puzzle games is too simple to justify additional obstacles like that. Your fire wall obstacles were perfect because they made me think about my movements without having to worry about timing them too carefully. That fits in with the "relaxing" type concentration that this game offers.
So what I would suggest for this game and its theme is something like collectible items. Ideally, non-required bonus items to start just so people like me who have OCD about winning games at 100% completion will have something to look forward to at the end. It'd be funny, albeit a little sexist, for example, if you didn't collect these items and a green guy came by at the end and took your girl... unless you had all the medallions, of course, in which case he wouldn't.
In other words, a relaxed theme game needs optional puzzles. When you start adding additional, mandatory mechanics, you break the theme and you break the user's love of the game.
I will say that I had a lot of love and enjoyment for this game and that trust was never violated. That's important. Keep it up! You're bound to go far :)