|Unrelated image because this is all rules, credit Kev Chu|
You need 5x[current level] EXP to get to the next level. So, to reach level 2/3/4/5 you'll need 5/15/30/50.
You can earn 1 EXP for:
- Showing up
- Almost dying
- Having a decent funeral for a dead ally (good luck if they were a sinful S.O.B.)
- As a group, successfully winning a fight against a more powerful enemy force
- “Wasting” gold (assuming silver standard) equal to 10xlevel grants 1 EXP. If it doesn’t “help” you in the dungeon, and it doesn’t make money on it’s own, it probably counts. Training and research are perfect, as is debauchery, statue funding and having songs written of your exploits
- Rolling a critical success, so long as it actually has an impact on the story. Always ignore Initiative rolls
- Rolling a critical failure. The DM will suggest a bad outcome, if you come up with something worse, you earn 1 EXP, otherwise 0
- Swearing a binding oath*. If you break it, you can’t get experience from oaths ever again, as well as some other nasty side-effects
- Being exceptionally clever, at DM’s discretion
Finally, at the end of the session, everyone votes on each of the following. That player gets +1 EXP:
- Most dramatic moment
- Most Valuable Player
- Wooden Spoon (whoever is lowest total experience)
If you have enough experience, level up next time you take a long/short rest, or at the start/end of a next session.
And that's it! Benefits include - being able to tempt someone with a juicy experience point, level drain dealing damage to experience easily, easy tracking, and unified progression rates. Players will pretty likely reach level 2 if they survive their first session, and I've so far had two players reach level 4 over the course of a whole campaign and a bit, which feels about right.
*Oaths are a bit different. You can solemnly swear to rescue the princess, and say "no, I don't want the experience" or casually agree to rescue the farmer's son from the dungeon and get the point. The oath has to matter and NPCs have to notice. Normally, you have to frame them in the negative. That is, there has to be some way to clearly say if you have failed your oath. Recovering your word once you've lost it is extremely tricky. NPCs will notice if you try and swear an oath but it doesn't stick. Then they'll start to wonder...
If you retire, your next character starts with experience equal to your current level. Dying gives you nothing, unless you died a capital-H Hero and the other players actually cared about you. If that's the case, see below
When you die, for real, you gain starting Karma equal to your half current level. You get +1 Karma: if you got a decent burial, if you dodged Hell, if you ended up in Heaven, for every notable act (the other players act as a judge of this), and if your new character is somehow related to the dearly departed. You lose a Karma for every time you have skipped out on Death, and if your death was entirely your own fault for absolutely no gain. You can spend 1 Karma to reroll your new character, 2 Karma to haunt the party as a ghost briefly, 2 for an heirloom item from the previous character, and 1:1 for the XP of the new character.
Beyond Level 4:
You stop gaining HD at level 3, and stop getting class abilities past level 4. Keep tracking experience though, you can spend it for various bonuses:
+1 Attack (costs 10 XP, max +4)
Test a stat for improvement (costs 3 XP)
+1 Save (costs 5 XP, max +10)
+1 Luck Point (costs 5 XP)