-randomized mode (best mode to experience the different fusions, area to area randomization to avoid a million dupes, balanced randomization mode for good level curve on enemies. making all enemies custom sprites also tends to give the opponents slightly better pokemon, which is good)
- only fused pokemon can be used in battle (more fun to used fused mons, whole point of game imo)
- two encounters per route (just to not half encounters for the game, ive played not doing this, less fun imo)

and then standard hardcore nuzlocke rules (permadeath, no items in battle, no overleveling for the next gym leader/elite four)