Metamagic

[kimnosuk]

D&D's metamagic is somewhat too powerful but interesting. You can choose which spell to empower and its spell slot costs more.

We can adapt this system into DCSS. From this improvement, lower leveled spell can be used at later game(with a lots of cost) and higher leveled spell can be even more powerful, at costs of giving up other utility spells.

E.G.
Silent Casting(cast with 1.5 times more mp, memorized cost with 1.5 times more spellslots.): This spell cast without any sounds. Like demons, you can cast this spell even under the area of Silence.)
Penetrating Sharpness(cast with 6 plus mp, only to spells that effected by MR): This spell is now uneffected by MR, but HD.

[duvessa]

why

[kimnosuk]

To increase early magic's usage in later game and give more choices to magic usres

[Arrhythmia]

This just strikes me as power creep OP.

[Shard1697]

Why should early magic be used more in later game?

[kimnosuk]

To increase the choices of later game. You can choose between 'empowering early magics' and 'cast high level magic'. Also, when player can't get book they want, Metamagic can be a another way to go through.

[KoboldLord]

In 3.x D&D, metamagic was 90% terrible and useless because it was basically never worthwhile to pay a feat and an extra spell level for a slightly improved effect as opposed to just using a higher-level spell. Another 5% was broken, degenerate combos made by combining a metamagic feat from one sourcebook with a spell from a separate sourcebook, because both books were written without any knowledge or consideration of the content of the other. The last 5% was divine metamagic, which was already broken and degenerate right out of the book it was originally printed in.

This is similar to the results I would expect in Crawl. Silent Spell would probably be worse than useless for almost the entire game, and even in silence scenarios it can get you killed because you are casting 33% fewer spells. The Penetration ability, on the other hand, would be pretty awful for the game if it applied on any hex or hex-like that is actually good, since those are usually extremely good when they land.

[lethediver]

Too meta for my tastes