To be succinct, this is the FPS dungeon crawler that I've always wanted.
Fancy Skulls is stylish, atmospheric and an overall enjoyable experience. Combat is slick, the exploration is straight-forward—not as much backtracking a la Heavy Bullets, which for all intents are purposes, is also good shooter— and the enemies are just too damn cool for their own good.
The rooms are randomly generated, with unique adversaries whom can be summoned at the player's will, introducing an element of strategy to your spelunking, and good performance is rewarded, which is good because the game gets challenging in the last half, though an end game boss is conspicuously absent.
My only complaint is that the game could use more variety of rooms. Maybe some different layouts that can be generated on each level, or even a randomized layout for each room? More challenge rooms would be great in the final version, as well. Maybe a boss? Regardless, the different weapon upgrades and abilities are just enough to keep the game fresh and entertaining.
Fancy Skulls is well worth the price of admission. I cannot wait for the completed version.