On the whole, I thought that this was a splendid romp through the action/arcade-style scroller!
The gameplay is obviously the meat and potatoes of a game, and thankfully, I believe that you've adequately fulfilled that obligation! You've paced things rather nicely in terms difficulty and skill/character acquisition.
Aesthetically speaking, I have no real complaints. All of the menus were navigable, and I knew exactly where everything was, whenever I needed it. I tend to shy away from comments regarding style of graphics or art, as such things are quite trivial (unless a game mechanic relies on a particular style,) but once again, they sufficed to show me what I needed to see, so no stars docked there!
Unfortunately, it is the matter of your writing that I began to deduct points. I'm typically not too critical of a game's story- especially for Flash games, as long as there's some semblance of a goal or purpose, I'm pretty easy to please. However, you have gone out of your way to craft a story as well as five characters who have LOADS of potential for development, or at least some form of banter...and effectively tossed the opportunity out the window. I've noticed that quality programmers and animators typically tend to not fare so well in the field of writing. This is absolutely fine- We've all got our strong suits (programming isn't one of mine, by the way,) so if you've invested so much time and energy into a quality game, I would advise at least consulting a proof reader to go over your finished script before release. Polished writing doesn't mean the next great video game plot, but consistent personalities and proper English in the text can really make the difference between at good game and a great game!
My only other real gripe is geared towards game balance. Overall, I believe you took every effort in making sure that each individual character was capable of fending for themselves. However, when it came down to selecting a group of three, I found that I couldn't mix and match an awful lot- at least not without coming to an agonizing defeat. For starters, entering into any new map without Selena in your party is absolute suicide. Barring random potion drops and Ray's self-healing spell, she's the only way your party is going to be consistently healed. She's also the only way that characters can revive, which is absolutely critical once the levels kick up in difficulty. Also, Josh is completely worthless as your leader when compared to the skills of others, but his support skills and wide attacking arc make him near essential as a partner (especially when grinding, as he makes collecting money a much quicker task.) This effectively puts those two as permanent members on my roster, leaving me room only to mix and match my party leader, as opposed to the (presumable) intention of encouraging mixing and matching of entire parties.
Aside from those complaints, this was a solid experience for me! Cheers!