SFD is hybrid of classic SRPG (turn based tactical role playing with party managing) and rogue like. The battle is fast paced and light-weighted so you can play SFD in spare time.

You are nameless adventurer exploring sigma-finite dungeon with the help of cats to defeat lich king Raeleus and false god NOG in the bottom of dungeon.
You explore random generated dungeon 8 floor each composed of 4 x 4 room.
Each room have either treasure or shop or enemies etc.
Adventurer can hire your companion up to hire point and enter battle when you encounter enemy. Hire point can be upgraded after level up.
Battle is traditional your turn - my turn battle. each character have 2 action point and each character's skill have either cooling-time or mana usage(For example, walk to move skill has 1 cooling-time so most character's can move once a turn only). What is special to this game's battle is using environment or traps in dungeon. Any unit has push skill, so you can push enemy into spike trap or explosive and give damages.
Mana and inventory is common to allies. Mana is recharged 1 after a turn and can be upgraded by skill.

SFD is simple and short but not an easy game. You should sacrifice you and your companion's lives to defeat evil NOG.