New Game Mode: Quest Mode

[Kit]

Currently games are pretty long - you can quit and continue of course, but that doesn't give you the feeling of playing small bites. As a different genre I would point to Cook Serve Delicious 2 - I can play a couple of restaurant rounds each day and keep at it.
With Slay the Spire - the long rounds leave me unsure to start if I'm not in the mood for something long.

With that in mind I would like to suggest a new Quest Mode.
- You are faced with a screen with a number of quests plus final boss.
- Each quest is about 1 level of length, maybe a bit shorter.
- The quests ramp up in difficulty, but perhaps in pairs with different flavours of monsters despite similar overall difficulty.
- Dying means failing the quest, but you keep your character/deck. If you die you still get to keep the new cards you added, but lose any relics.
- You have a maximum of relics you can start a quest with (eg. 10), so if you have 13 relics having gained more in the previous quest, then next quest it will ask you to clean out 3 relics.
- 'Stronger' cards and relics appear in the later harder quests.
- Developed with a certain grind in mind, having to do each level of quest a few times in order to have a strong enough deck to take on the next set of quests.
- You can have multiple character slots since quest mode takes a long time, so you can have several deck styles on the go.

Benefits of my suggestion:
- No new monsters/cards/etc. needed. It is just re-using the same content in a different way.
- Allows for short play sessions. You can finish a quest and feel satisfied it is complete (quitting mid-adventure in normal mode isn't so nice)
- Allows a different kind of enjoyable grind to build up particular characters
- Shorter regular sessions less likely to lead to "burn out" where you stare at the game in the library and think, 'Umm, do I really feel like starting a long game...'

Although this could be implemented with no changes to cards - I might suggest some additional card upgrade mechanics. Maybe spread card upgrades over more levels, and maximum upgrade level your character can have depends on the number of quests you have beaten (and you can only upgrade to that level at that just-beaten level, not grind out super-easy upgrades back at Quest 1).
But still - the minimum and maximum levels could be the same so you don't need to worry about balance too much, and some cards who clearly only have two levels (such as cost reduces from 1 to 0) could be enabled at different levels (eg. level 2 no upgrade, level 3 no upgrade, level 4 upgrade possible), while other damage based cards would more easily spread across multiple levels.

[Kit]

Update to the idea:

- You don't keep new cards from quests. You win crystals. Crystals can be spent on chests (eg. booster packs).
- Chests - common / uncommon / etc. Common only contains cards, but more expensive rarity chests might contain relics / card upgrade / card delete etc.
- Opening chest style can refer to Idle Champions of the Forgotten Realms idle game, they have a nice style for opening chests.