Morph techtree and XP

Units get experience for destroying enemy units. Accumulating enough XP can increase the unit's rank. Each rank is attained by the unit destroying its worth of metal of enemies. This is split equally between doing the damage, and dealing the finishing blow, ie. bringing an enemy unit of the same cost down from full to 1 health is worth half a rank, and getting the last blow another half.

Experience gain can get modified. EMP damage is scaled to 10% and then the inverse of the target health - for example, a unit on 1/4 health will give 40% of the normal value. Disarm and slow damage don't give XP. Mixed damage gives XP for the real damage part. Overkill damage and EMP that doesn't add further stun time is discarded - only the actual damage done counts.

Ranks can enable morphing for certain units. After morph, the rank is rescaled by its new cost, eg. if the unit is rank 6, but then morphs to a unit 3x as expensive, it will now be rank 2. Currently all morphs that require XP require rank 3, ie. making the base unit's cost 3 times. Provided that your unit is experienced enough, it can morph again right away. For example, a Warrior costs 220, so it needs to kill 660 metal worth of enemies to be able to morph to Zeus: if a Glaive destroyed 660m worth of enemies, it will be able to morph to Zeus right away after morphing to Warrior.

The cost of morph is the difference between the target unit's cost and the morpher's cost; it's free if target is cheaper. The morph times are given in the techtree in seconds.

Here's the morph techtree (green is XP-free morphs, red is XP-enabled (rank 3)):


For the legacy XP system (before v1.2.9.6), see this post.

Nope, its morph is inaccessible. Disarm gives no XP. It's a holdover from the time when it was EMP (as EMP gives XP).

Edit: removed this morph from the tree and submitted a PR to remove it from the game.

Old techtree had Crabe morph to Dante instead of Scorpion, which allowed Fleas to become Detriments:
B138192 2 on Hide_and_Seek_v03

Edit: updated to new Chainsaw buildpic. Thanks!

The ships have no morphs, though they used to:
Skeeter -> Typhoon -> Crusader -> Enforcer -> Warlord
Snake -> Serpent

This is the legacy XP system. It has been replaced by the simplified one in the OP.

Units get 0.1 XP for making cost through damage, and 0.1 XP for making cost through last-hitting. This means that a unit that single-handedly kills its cost 100% -> 0 and deals the finishing blows will have 0.2 XP; this is also why light units tend to have inflated XP values - if they score the finishing blow, they get as much XP as they would get for bringing the unit down from 100% to 0.

XP gain can get modified. Units are worth up to 30% more based on their XP, with 15% more at XP = 1 - the exact formula for added worth is 0.3*XP/(XP + 1). For example, a 0 XP unit who kills its cost in 1.0 XP units will get 0.23 XP. Conversely, experienced units get a bit less XP for units with less XP. EMP damage is scaled to 10% and then the inverse of the target health - for example, a unit on 1/4 health will give 40% of the normal value. Disarm and slow damage don't give XP. Mixed damage gives XP for the real damage part. Overkill damage and EMP that doesn't add further stun time is discarded - only the actual damage done counts.

Units get ranks for XP. Each rank requires XP. Currently all morphs that require XP require rank 3. Here's some example values on how much XP is rank 3 (making cost once is 0.2):

quote: Flea - 1.10 Glaive - 0.87 Gremlin - 0.73 Jack - 0.56 Reaper - 0.52 Crabe - 0.46 Bantha - 0.31

Units keep half their XP after morph. However, you can't chain-morph because units with further XP morphs will also get trimmed to 90% of the next morph threshold. For example, Glaive can morph at 0.87 XP, so a Flea morphed to a Glaive will never have more than 0.87 * 0.9 == 0.78 XP after morphing.

Is there any particular reason why EMP damage should give XP while disarm/slow damage should not?

(Elite Freakers, maybe?)

I once morphed flea to detri

I still want detri to morph to golden flea...

So a Zeus gets more than one rank by killing another Zeus?

Yes, Zeus gets more than one because there's also EMP.