Devil Daggers is everything it needs to be. It doesn't make vain attempts to appeal outside its intended purpose, and it holds up to the definition of "game" as well as anything like Tetris, Chess or Pac Man. It is a hardcore twitch-action shooter/first person bullet hell that has only one scoring method: how long can you last? The design of enemies, the weapon, the spawns, the lighting in the arena, and the sound are all very well executed and serve the game's purpose effectively. It has a very compelling game loop where enemy spawns get tougher and more numerous, and your weapon gets more powerful and satisfying. In terms of pure game design, Devil Daggers is simply excellent.
