I like the color palette of the game and the simple character design, but (except for the ninja), they were not easily recognizable: it took me a while to get the one I wanted when I managed to have a lot of them. The rooms were quite empty and a bit too linear in general (I have the same problem in my game), but my main issue is with the main concept of the game itself. Having a lot of characters in a snake-like fashion, despite looking cool, it's kinda useless when you can use just one of them while the others just stand still getting shot. To make it work a bit better, the rooms should have been much bigger, in order to give the player at least the possibility to dodge the attacks more easily. I managed to arrive to the boss room using always the same character, but by that time most of the group was already dead. On a last note, the weapons are a bit too unbalanced in my opinion, and the arc-trajectory of the grenades made me think that they could overcome the walls. On a last note on the last note, to be really picky I don't think that the game can be classified as a roguelike.
The idea is really solid and with some polish it could be a great base for a great game, you should keep working on this, good job!