I love the fact that they took the story and went with it and made an open-world platformer. The music is just as nice as the original game as well. I also really like how this game is modelled after the gungeons from Black Butler. I don't know if there is anything else like it on the market, but the style and design of the game just reminded me of the original. There is a bit more puzzle and platforming involved, but the original gungeon series is definitely my favorite. I don't want to give too much away, so I'll just tell you this one thing: If you enjoy shooting things from the ground (or the air), then this game will be the perfect game for you.
If you're looking for a great action/adventure PC game that will keep you on your toes, then I would highly recommend Mod the Gungeon for ETG. You'll immediately notice the influences of the gungeon series as soon as you load up the game, and the only difference is that you have to prevent evil monsters instead of shooting them. Needless to say, this is easily one of my favorite games on the Internet right now.