Ideas for Castlevania Harmony of Dissonance:
→ New Game Plus. This and Circle of the Moon could use a NG+ in a style similar to Aria of Sorrow, where relics/abilities and keys are lost but all else is kept. (Floating/Infinite Boots would be kept, since they are already endgame gear anyways. Plus it'd be funny to "break" the game after you are done with it)
→ Make it so Crush Boots, Night Goggles and Crushing Stone's effects are applied once you get them, without having to equip first. (However, in Crushing Stone's case, the crushing property is the only effect applied without equipping, and the charging is faster and causes more damage to compensate)
→ Increase the odds of Rare Ghost appearing and add more rooms where it can appear.
→ Add a custom item named "Danasty's Scroll" that reduces all subweapon heart usage greatly, with knives becoming free.
→ Change "Cristopher's Soul"/"Bullet Tip" behavior to allow it to be used regardless of full health or not, but to balance reduce the ATK.
→ Change "Sylpha's Soul"/"Cypher's Charm" behavior to greatly increase MP gain (almost similar to Chaos Ring in Aria of Sorrow) at the cost of greatly lowering ATK and DEF.
→ Add a "Sylpha mode", possibly with the name "BELNADES": start with lower HP, Heart, DEF and ATK, but high INT, MP and all books.
→ Add a "Grant mode", possibly with the name "DANASTY": start with lower MP, ATK, DEF and INT, but high HP, LUCK and Heart.