Check the notes for his twitter to see the pictures (and where he uploaded other pages of stuff like early Alphys design) and bits I think were interesting

Notes:

"Karma system, higher karma higher chance to run away from fights, etc. lower karma and it's harder etc"
"Black market buy stuff with karma"
"A button to 'phase' through bullets, some bullets weren't affected by phasing"
Magic, "Spells Shrink, Speed up, heal, attack all, attack up"
"Shrink would shrink your hit box but make you do less damage"
"You can date all the bosses except the last one and the robot, can date the hot robot"
Other neat stuff if you're interested but if I keep going someone will complain about the notes (and probably will anyway)