diff --git a/src/lib/eventsystem/event/ArtifactCountChangedEvent.h b/src/lib/eventsystem/event/ArtifactCountChangedEvent.h
index 258d99b..31d5ad2 100644
--- a/src/lib/eventsystem/event/ArtifactCountChangedEvent.h
+++ b/src/lib/eventsystem/event/ArtifactCountChangedEvent.h
@@ -2,10 +2,9 @@
 
 #include "Event.h"
 
+// Fired when the collected artifact count changes. Carries no payload —
+// subscribers re-read Simulation::getArtifactCount(), and the win count from
+// world.artifacts.artifactWinCount.
 class ArtifactCountChangedEvent : public Event
 {
-public:
-    ArtifactCountChangedEvent(int count, int winCount) : count(count), winCount(winCount) {}
-    const int count;
-    const int winCount;
 };
diff --git a/src/lib/eventsystem/event/BossWaveUpdatedEvent.h b/src/lib/eventsystem/event/BossWaveUpdatedEvent.h
index 5fbf24d..47ff228 100644
--- a/src/lib/eventsystem/event/BossWaveUpdatedEvent.h
+++ b/src/lib/eventsystem/event/BossWaveUpdatedEvent.h
@@ -2,16 +2,11 @@
 #define BOSS_WAVE_UPDATED_EVENT_H
 
 #include "Event.h"
-#include "Tick.h"
 
+// Fired when the boss wave counter or its countdown changes. Carries no payload —
+// subscribers re-read Simulation::getBossWaveCounter() and getBossCountdownTicks().
 class BossWaveUpdatedEvent : public Event
 {
-public:
-	BossWaveUpdatedEvent(int counter, Tick countdownTicks)
-	    : counter(counter), countdownTicks(countdownTicks) {}
-	const int  counter;
-	const Tick countdownTicks;
 };
 
 #endif   // BOSS_WAVE_UPDATED_EVENT_H
-
diff --git a/src/lib/eventsystem/event/BuildingBlocksChangedEvent.h b/src/lib/eventsystem/event/BuildingBlocksChangedEvent.h
index 2b02b8a..62e0706 100644
--- a/src/lib/eventsystem/event/BuildingBlocksChangedEvent.h
+++ b/src/lib/eventsystem/event/BuildingBlocksChangedEvent.h
@@ -3,12 +3,10 @@
 
 #include "Event.h"
 
+// Fired when the building block stock changes. Carries no payload — subscribers
+// re-read Simulation::getBuildingBlocksStock().
 class BuildingBlocksChangedEvent : public Event
 {
-public:
-	explicit BuildingBlocksChangedEvent(int blocks) : blocks(blocks) {}
-	const int blocks;
 };
 
 #endif   // BUILDING_BLOCKS_CHANGED_EVENT_H
-
diff --git a/src/lib/eventsystem/event/ExpansionCostChangedEvent.h b/src/lib/eventsystem/event/ExpansionCostChangedEvent.h
index dcd7b1e..682e90e 100644
--- a/src/lib/eventsystem/event/ExpansionCostChangedEvent.h
+++ b/src/lib/eventsystem/event/ExpansionCostChangedEvent.h
@@ -4,14 +4,11 @@
 #include "Event.h"
 
 // Fired when the current asteroid-expansion cost changes (REQ-EXP-COST): once at
-// startup and again after each expansion is purchased. Carries the cost in
-// building blocks so the header Expand button can update its caption/enabled
-// state (REQ-UI-EXPAND-BUTTON).
+// startup and again after each expansion is purchased. Carries no payload — the
+// header Expand button re-reads Simulation::getCurrentExpansionCost() to update
+// its caption and enabled state (REQ-UI-EXPAND-BUTTON).
 class ExpansionCostChangedEvent : public Event
 {
-public:
-	explicit ExpansionCostChangedEvent(int cost) : cost(cost) {}
-	const int cost;
 };
 
 #endif   // EXPANSION_COST_CHANGED_EVENT_H
diff --git a/src/lib/eventsystem/event/TickAdvancedEvent.h b/src/lib/eventsystem/event/TickAdvancedEvent.h
index 3f95ccb..01567c1 100644
--- a/src/lib/eventsystem/event/TickAdvancedEvent.h
+++ b/src/lib/eventsystem/event/TickAdvancedEvent.h
@@ -2,14 +2,11 @@
 #define TICK_ADVANCED_EVENT_H
 
 #include "Event.h"
-#include "Tick.h"
 
+// Fired when the simulation tick advances. Carries no payload — subscribers
+// re-read Simulation::getCurrentTick().
 class TickAdvancedEvent : public Event
 {
-public:
-	explicit TickAdvancedEvent(Tick tick) : tick(tick) {}
-	const Tick tick;
 };
 
 #endif   // TICK_ADVANCED_EVENT_H
-
diff --git a/src/ui/GameWorldView.cpp b/src/ui/GameWorldView.cpp
index 7b22056..518ca33 100644
--- a/src/ui/GameWorldView.cpp
+++ b/src/ui/GameWorldView.cpp
@@ -403,26 +403,26 @@ void GameWorldView::onFrame()
         {
             m_lastTick = newTick;
             EventManager::getInstance()->sendEventImmediately(
-                std::make_shared<TickAdvancedEvent>(newTick));
+                std::make_shared<TickAdvancedEvent>());
         }
         if (newBlocks != m_lastBlocks)
         {
             m_lastBlocks = newBlocks;
             EventManager::getInstance()->sendEventImmediately(
-                std::make_shared<BuildingBlocksChangedEvent>(newBlocks));
+                std::make_shared<BuildingBlocksChangedEvent>());
         }
         if (newExpCost != m_lastExpansionCost)
         {
             m_lastExpansionCost = newExpCost;
             EventManager::getInstance()->sendEventImmediately(
-                std::make_shared<ExpansionCostChangedEvent>(newExpCost));
+                std::make_shared<ExpansionCostChangedEvent>());
         }
         if (newBoss != m_lastBossCounter || newCountdown != m_lastBossCountdown)
         {
             m_lastBossCounter   = newBoss;
             m_lastBossCountdown = newCountdown;
             EventManager::getInstance()->sendEventImmediately(
-                std::make_shared<BossWaveUpdatedEvent>(newBoss, newCountdown));
+                std::make_shared<BossWaveUpdatedEvent>());
         }
 
         // Unlocked building set changes only after a drop is applied or on Restart
@@ -485,8 +485,7 @@ void GameWorldView::onFrame()
     {
         m_lastArtifactCount = currentArtifactCount;
         EventManager::getInstance()->sendEventImmediately(
-            std::make_shared<ArtifactCountChangedEvent>(
-                currentArtifactCount, m_sim->getConfig().world.artifacts.artifactWinCount));
+            std::make_shared<ArtifactCountChangedEvent>());
     }
 
     update();