The manual will actually be provided within the game menu. However, I will explain here as well. The game can be controlled with keyboard.
For Keyboard:
W A S D -> Will be for moving in up, left, down, right respectively
Mouse -> Direction of aiming
Mouse Left Click -> Shoot
Mouse Right Click -> Use skill
Space -> Action

Guide:

This game is a 2.5D top down shooter that has a story about a character that is trapped inside a dungeon without knowing any reason why she’s there. It has five stages with different types of enemies which are melee creeps, ranged creeps, and boss. The dungeon has boxes to prevent the player from getting hit from the enemies. On the end of the game, there will be a boss which has special attack patterns that is relatively hard to beat with its attack patterns.