So I was just creatively scribbling for ideas and I ended up with this...

Tower of dio (boss rush)

Basically I made this final boss for retro city....

cowboy sans ( against heartale_sans )

So basically I decided in your "Customize character" part, there will be the choice to change races. (Races are above)

added HeartTale True!fresh sans

Behold retro city!

ill give out this character for those who join the game on date of release, so far this is its ultimate move, and needless to say after the time it can only be given by trade. (Fullscreen to see)

Not my best work but im proud of it :D

Tbh I think this couldn't get any worse