Really cool game! The art, audio, and story all fit together really nicely to make a motivating arcade game. It honestly reminded me a lot of "Realm of the Mad God" with the RPG & Bullet Hell genres combined, but you made it into a side-view game instead of top-down, which I must say looks and plays better than ROTMG.
The gameplay also felt really good. The movement was clean, the dodging was satisfying and felt fair to use (especially against those orcs, they move so fast), and the shooting had good damage and fire rate. I did feel like the starting character's damage was too weak and that it was impossible to progress far with him, but it seems like that was intentional for showing off the "game over isn't the end" theme, plus the other 3 characters felt balanced against most of the enemies, so I guess that's fair.
I did find that it was difficult to survive properly because the intense particle effects from every single shot blinded me from my enemy's shots. Especially as the ginger hero, it was impossible for me to see where my enemy was shooting, so I died with that character really fast. If you make the shot impact smaller in scale, faster in animation, and with little-to-no camera shake, then it would feel a lot better to me.
I got to wave 5 before I died, so I don't know if there's unlimited waves or only a set few. If there's unlimited, then I'd recommend having a scoreboard somewhere to see who's got the highest score. It would really boost the "arcade" feeling this game seems to be exuding. If not, then I'll have to beat all the waves sometime!
Overall, great use of the theme that makes narrative and mechanical sense, simple yet elegant art style, fun and engaging gameplay, and a simple yet effective concept. Nice job!