Mustrum_Ridcully
Legend
You don't need many house rules to make combats harder. Just send the PCs against more high level monsters, and give them less opportunities for short or extended rests.
When they enter a dungeon, the start with a small battle of their level. This alerts other monsters in the area, that come before they can have a short rest (probably while still fighting), effectively increasing the encounter level by 2 to 3 points. If this has cost them most of their dailies and healing surges, retreat is still not an option. They are either on the clock (and have to go on), or they are chased by another group of monsters, before they can take an extended rest. This encounter doesn't have to be tough as the one before their level or their level +1 might be enough. They still have all their encounter powers, but they will need to use them.
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There is one thing that might not be covered by different encounter mechanics - extended rests. For a gritty game, you need to lessen their effect.
For example - they regain only 1/4 of their healing surges (rounded down). Some care increases this to 1/3, and a bed rest to 1/2. So it requires at least two days to recover fully (if you want, you can invent restoration rituals that improve that, but cost a fair amount of component cost.)
You might also reduce the number of daily powers recovered - maybe just 1 daily and one utility power per rest.
Also, use more disease effects, maybe invent some to model wounds. There have been quite a few suggestions in the past. Yesterday I stumbled on this site: Wyatt And Friend’s 4e Houserules « The Spirits of Eden
There are some suggestions on "grim & gritty" there, too, from various sources.
When they enter a dungeon, the start with a small battle of their level. This alerts other monsters in the area, that come before they can have a short rest (probably while still fighting), effectively increasing the encounter level by 2 to 3 points. If this has cost them most of their dailies and healing surges, retreat is still not an option. They are either on the clock (and have to go on), or they are chased by another group of monsters, before they can take an extended rest. This encounter doesn't have to be tough as the one before their level or their level +1 might be enough. They still have all their encounter powers, but they will need to use them.
---
There is one thing that might not be covered by different encounter mechanics - extended rests. For a gritty game, you need to lessen their effect.
For example - they regain only 1/4 of their healing surges (rounded down). Some care increases this to 1/3, and a bed rest to 1/2. So it requires at least two days to recover fully (if you want, you can invent restoration rituals that improve that, but cost a fair amount of component cost.)
You might also reduce the number of daily powers recovered - maybe just 1 daily and one utility power per rest.
Also, use more disease effects, maybe invent some to model wounds. There have been quite a few suggestions in the past. Yesterday I stumbled on this site: Wyatt And Friend’s 4e Houserules « The Spirits of Eden
There are some suggestions on "grim & gritty" there, too, from various sources.