I'm a tad bit confused over upgrading. You upgrade from level one to two and then to three, and then back to one again and then another card has two or is level two but upgraded but maybe not so let's fuse, but no, they look the same but one of the cards is upgraded but still has the same color as the ones who are not upgraded but the have both ... you get my point?
The frame's change. If you notice, they will start to gain bulk with every fuse. Each fused card is better than their non fused counterparts. You can fuse a card a total of two times (for a total of four cards). The rarity doesn't change during this process - all rarities can be upgraded and fused. Hopefully this helps!
Station Market. Purchasing goods using keypad numbers works once. Then you have to press buy button for one item at a time instead. Auto enabling multiple weapons or drills simultaneously would be appreciated. Add an active/passive jobs button or perhaps a log would be nice too.
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The frame's change. If you notice, they will start to gain bulk with every fuse. Each fused card is better than their non fused counterparts. You can fuse a card a total of two times (for a total of four cards). The rarity doesn't change during this process - all rarities can be upgraded and fused. Hopefully this helps!