Here are some brief impressions after trying the game.
The setting is great. Playing as the four horsemen is a good idea, and the mapping with it's color-scheme and details support the premise well. Does this game have an original soundtrack? I hadn't heard these pieces before, so it was refreshing, and the music mostly fits well. The battle theme could be a bit more dark though, to be more suitable with the setting, but that's just my personal opinion.
There are two problems that were my main gripes after trying this game. First of all, the personality traits of the horsemen are not well enough defined. They all sound kind of the same, and the snarky tone of the dialogue- in my opinion- is not serving the general atmosphere too well. The dialogue sounds too "modern" against the setting.
Another issue comes with the skills: There are a bunch of skills immediately assigned to each horsemen. Of course, it makes sense that these guys- the Four Horsemen- are quite powerful from the beginning, but there's simply too many skills to pick from at the start. It would possibly be better to introduce some of these skills later, as rewards from exp or some other mechanic, so that the player could adjust to the new skills and learn to use them as they come. The difficulty level in the easiest setting is too hard... although, it says "hard" in the difficulty-select screen too, so... : -D
I like the way you've handled the battles in general, and the battle system works really well. Is this a system you created yourself? if so, great work, even though i prefer bigger enemy sprites. This feels original, however and that's the most important thing. Also, very nice work with the battle backgrounds.
To be honest, i'm not exactly a fan of dungeon crawler genre, which is probably the main reason why i lacked the interest to play it through further. For the fans of the genre, this is probably a good enough game.
These are very brief impressions after playing through a couple of bosses, and should not be viewed as a review.