Yes, the price of stones doubles or triples between floors, but the gold you get from training fights gets 5x or 6x. For example, at first floor, I was getting about 180 gold a fight, with 500 gold stones. 2nd floor, about 1k gold a fight, with 1k gold stones. 3rd floor, about 6.5k gold a fight, with 3k gold stones. 4th floor, about 32k gold a fight, with 8k gold stones. Gold and stones both scale well.
Secret ending that you get from beating is Neferiti I believe, seeing that on the high scores list, the only character ending that is missing is Neferiti (but there is conveniently a ???? entry). Plus her ending selection was at the very bottom.
Hold down the space bar. Select your training of choice. Watch as losing as quickly as you can from training ends up earning you faster stats than actually trying at the training minigames.
@Thriek, Abyss mode is not impossible. There is still a cap of 8k gold. Getting to 8k gold cap is the harder part of Abyss mode compared to Hard. Once you get to the 8k gold cap, difficulty drops back down to the Hard mode.
After a while, the only thing you need to know is samurai > ninja > monk > sword man > samurai. I swear, we went through this cycle about 10x before the abyss mode computer switched to a different unit other than samurai/ninja/monk/sword man.
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