It mainly evolves around this question: "Will the increases per level on creatures' stats and XP, players' required XP and items' stats be based on a linear function, power function or an exponential function?"
Many games used formulas that cause big differences between levels in the lower levels and little differences between levels in the higher levels.
I hope you guys use formulas that create fairly equal differences between levels all around.
Formula of increase per level
There will probably be an increase each level in the stats of the creatures and items, the XP and gold that creatures give and the XP that it takes for a player to get to the next level. With that I mean that a level 2 item generally is better than a level 1 item, a level 2 creature is stronger than a level 1 creature, a level 2 creature gives more XP than a level 1 creature, etc.
The formulas that deal with these things can be of several types. It will have little effect in the early levels which types you choose but their effects increase with each level and at higher levels the effects are large.
Linear formula
A linear formula looks like this: Y = A * X + B.
Four examples of linear formulas are found in Fallensword. The stats of items and creatures, and the gold and XP that creatures give are linearly related to their level.
- There the gold that the creatures give on average is the same as its level (so Y = X). So a level 100 drops around 100 gold and a level 200 drops around 200 gold.
- The total stats of common items is twice the level of the item (So Y = 2 * X). The stats are randomly divided over (most of the time 2 of) the 5 possible stats. So a level 10 item has 20 stat points divided over several stats, and a level 100 items has a total of 200 stat points.
- The total stats of creatures is also based on a (fairly) linear formula. A level 400 creature has around 8200 stat points (excluding HP) and a level 600 creature has around 12300 stat points (excluding HP).
You have to wait until level 20 before you encounter an item that has double the stats of a level 10 item, and you have to wait for a level 200 item before an item has double the stats of a level 100 item.
The difference between items of level 1, 2, 3, etc. is very big so players will want to switch to the higher level items as soon as possible. But at level 100 their is little urge for a player to change items because the level 101, 102, etc. simply aren't all that better; they just add 1% or 2% extra, and that's likely not enough to buy them from a vendor or hunt them yourself.
The same goes for creatures. A level 1 player has a very hard time defeating a level 2 creature as it is twice as strong as the level 1 creature. But those differences aren't that big a few levels later. If a level 100 player can defeat a level 100 creature then he can probably also defeat a level 101, 102, 105 or 110 creature with nearly the same ease.
Power formula
A slightly different kind of formula would be a power function. A simple power formula would look like this: Y = A * X^B + C.
This formula is used for the XP that players need in Fallensword for the next level. The total XP needed for a level = 10 * Level^3 = 10 * Level * Level * Level.
And as a result the XP needed to get to the next level = 30 * Level * (Level-1) + 10.
The same thing here appears as with the linear system: it takes a lot more XP each level in the first few levels, but it is slowly reduced to close to nothing in the higher levels.
For example, a level 10 player needs 3,310 XP to get to the next level (10,000 -> 13,310) and a level 14 player needs nearly double that (6,310 XP) to get to level 15 (27,440 -> 33,750). But on the other hand a level 100 player needs 303,010 XP to get to level 101 (10,000,000 -> 10,303,010) and it's not until level 142 that the XP required for another level is doubled (600,670 XP (28,032,210 -> 28,632,880)).
The problem is that at higher levels there are no real differences between levels any longer.
- It doesn't matter if your items are a lot of levels old because they give nearly the same stats as those of your own level,
- it doesn't matter if you kill creatures that are below your level because their XP and gold are quite close to the creatures of your own level,
- it doesn't matter if you fight creatures above your levels because their stats are very close to the creatures of your own level.
Exponential formula
A simple solution to this problem would be an exponential system. A simple exponential function looks like this: Y = A * B^X + C. It looks very similar to the power function, but X and B are reversed which makes all the difference.
I will give a few examples of how this could work with XP and stats.
Creatures
With an exponential function the creatures will become stronger each level based on how large "B" is in the formula example above. If "B" is 1 then creatures will remain as strong as the level 1 creature, if "B" is 2 then creatures will double in strength per level (probably a bit too steep an increase).
Let's put "B" at 1.1 in this example. This means creatures will become 10% stronger each level.
Suppose the level 1 creature has 100 stat points (divided among the different stats (attack, armor, damage, etc.)) then the level 2 creature has 110 stat points, the level 3 creature has 121 stat points, the level 4 has 133 stat points, the level 4 creature has 146 stat points, the level 5 creature has 161 stat points, etc.
This will keep the differences between creatures/levels interesting at the low as well as the high levels because the difference between a creature and one that is 1 level above or below it is always 10%.
Items
The stat increases on items will probably have to keep pace with the increase in the creatures' stats because else it will only become more and more difficult to defeat creatures until a point is reached where it becomes impossible.
So an item of a certain level will be 10% stronger than an item of 1 level lower and 21% stronger than an item of 2 levels lower. This means it will always be interesting to get the highest level items you can get, even at the higher levels.
XP from creatures
Creatures could also give XP based on an exponential function. It would penalise hunting below your level (weaker creatures) because they give less XP than the creatures of your own level. And it will stimulate hunting at your level (or if possible above your level) because the tougher creatures give more XP than those of your own level.
It would make sense to have the XP increase at the same rate as the increase in strength of a creature or perhaps a little bit less than that; otherwise creatures above your level are a bit stronger (10%) but give a lot more XP (20%). So it would work well if "B" would be around 1.08. At 1.08 a creature will give 8% more XP than a creature 1 level below its own level, it will give 16.64% more XP than a creature 2 levels below its level and 25.97% more than a creature 3 levels below it.
XP required for next levels
Creatures give 8% more XP each level. It would make sense that the XP that is required to get to the next level will increase exponentially as well. Otherwise the time/effort/amount of kills per level will either increase a lot the higher you get, or decrease a lot the higher you get.
If "B" in this formula is lower than the "B" in the formula for the creatures' XP then the amount of kills to get a level will drop the higher we go which probably makes little sense. If "B" is higher then it will increase the higher we go and if it's the same then it will remain the same.
Suppose "B" is 1.1 here, and at a certain level the XP per creature is 1000 and the extra XP needed for the next level is 100,000. That means 100 creatures have to be killed for another level.
The next level the creatures will give 1080 XP and the player needs 110,000 XP; which is 101.85 kills. The levels after that it is: 1166 XP / 121,000 XP - 103.77 kills; 1260 XP / 133,100 XP - 105.63 kills; 1360 XP / 146,410 XP - 107.65 kills; 1469 XP / 161,051 XP - 109.63 kills; etc. So the amount of kills per level slowly rises this way. In this example the amount of kills per level doubles every 38 levels so it's 200 at level 39, 400 at level 77 and 800 at level 115.
So basically I am wondering if you guys have thought about this and which type of formulas you guys are using.
I'm sorry if the math is giving you guys headaches, but they were necessary to explain things.
If things are still unclear just ask and I'll explain it better (and probably less mathy).