Can now play an entire scenario with no improvements or techs defined

core/src/com/unciv/logic/civilization/CivilizationInfo.kt

@@ -283,6 +283,8 @@ class CivilizationInfo {
     }
 
     fun getEra(): String {
+        // For scenarios with no techs
+        if (gameInfo.ruleSet.technologies.isEmpty()) return "None"
         if(tech.researchedTechnologies.isEmpty())
             return gameInfo.ruleSet.getEras().first()
         val maxEraOfTech =  tech.researchedTechnologies

core/src/com/unciv/ui/newgamescreen/GameOptionsTable.kt

@@ -124,6 +124,7 @@ class GameOptionsTable(val previousScreen: IPreviousScreen, val updatePlayerPick
     }
 
     private fun Table.addEraSelectBox() {
+        if (ruleset.technologies.isEmpty()) return // scenario with no techs
         val eras = ruleset.technologies.values.map { it.era() }.distinct()
         addSelectBox("{Starting Era}:", eras, gameParameters.startingEra)
         { gameParameters.startingEra = it }

core/src/com/unciv/ui/worldscreen/unit/UnitContextMenu.kt

@@ -27,14 +27,15 @@ class UnitContextMenu(val tileMapHolder: WorldMapHolder, val selectedUnit: MapUn
             onMoveButtonClick()
         }
 
-        addButton(
-                ImageGetter.getImprovementIcon("Road"),
-                "Construct road",
-                BuildLongRoadAction(selectedUnit, targetTile)
-        )
+        // Basic scenarios sommetimes don't have roads
+        if (selectedUnit.civInfo.gameInfo.ruleSet.tileImprovements.containsKey("Road"))
+            addButton(
+                    ImageGetter.getImprovementIcon("Road"),
+                    "Construct road",
+                    BuildLongRoadAction(selectedUnit, targetTile)
+            )
 
         pack()
-
     }
 
     fun addButton(icon: Actor, label: String, action: MapUnitAction) {