diff --git a/src/game_actor.cpp b/src/game_actor.cpp
index fbf871a419..c8839ee34a 100644
--- a/src/game_actor.cpp
+++ b/src/game_actor.cpp
@@ -149,7 +149,7 @@ bool Game_Actor::IsItemUsable(int item_id) const {
 	if (query_set->size() <= (unsigned)(query_idx)) {
 		return true;
 	}
-	return query_set->at(query_idx);
+	return (*query_set)[query_idx];
 }
 
 bool Game_Actor::IsSkillLearned(int skill_id) const {
@@ -1432,7 +1432,7 @@ PermanentStates Game_Actor::GetPermanentStates() const {
 		auto& states = item->state_set;
 		// Invalid states in armor already reported earlier in
 		// calls to AdjustEquipmentStates.
-		int num_states = std::min(states.size(), lcf::Data::states.size());
+		int num_states = std::min<int>(states.size(), lcf::Data::states.size());
 		for (int i = 0; i < num_states; ++i) {
 			if (states[i]) {
 				ps.Add(i + 1);
diff --git a/src/game_battlealgorithm.cpp b/src/game_battlealgorithm.cpp
index 32894bf1e3..a475086e9f 100644
--- a/src/game_battlealgorithm.cpp
+++ b/src/game_battlealgorithm.cpp
@@ -963,7 +963,7 @@ bool Game_BattleAlgorithm::Normal::Execute() {
 			} else {
 				auto& a1 = weapon1->attribute_set;
 				auto& a2 = weapon2->attribute_set;
-				std::vector<bool> attribute_set(std::max(a1.size(), a2.size()), false);
+				lcf::DBBitArray attribute_set(std::max(a1.size(), a2.size()), false);
 				for (size_t i = 0; i < attribute_set.size(); ++i) {
 					if (i < a1.size())
 						attribute_set[i] = attribute_set[i] | a1[i];
diff --git a/src/game_battler.cpp b/src/game_battler.cpp
index 9b37e5a322..bb4c7a0eb8 100644
--- a/src/game_battler.cpp
+++ b/src/game_battler.cpp
@@ -140,7 +140,7 @@ int Game_Battler::GetAttributeRate(int attribute_id, int rate) const {
 	return 0;
 }
 
-float Game_Battler::GetAttributeMultiplier(const std::vector<bool>& attributes_set) const {
+float Game_Battler::GetAttributeMultiplier(const lcf::DBBitArray& attributes_set) const {
 	constexpr auto min_mod = std::numeric_limits<int>::min();
 	int physical = min_mod;
 	int magical = min_mod;
diff --git a/src/game_battler.h b/src/game_battler.h
index 9a3523a6a6..a3bfe74917 100644
--- a/src/game_battler.h
+++ b/src/game_battler.h
@@ -23,6 +23,7 @@
 #include <vector>
 #include <limits>
 #include <lcf/rpg/state.h>
+#include <lcf/dbbitarray.h>
 #include "system.h"
 #include "state.h"
 #include "color.h"
@@ -203,7 +204,7 @@ class Game_Battler {
 	 * @param attributes set for the incoming action
 	 * @return effect multiplier
 	 */
-	float GetAttributeMultiplier(const std::vector<bool>& attributes_set) const;
+	float GetAttributeMultiplier(const lcf::DBBitArray& attributes_set) const;
 
 	/**
 	 * Gets the characters name
diff --git a/src/game_map.cpp b/src/game_map.cpp
index efb125ae10..bb56107eaa 100644
--- a/src/game_map.cpp
+++ b/src/game_map.cpp
@@ -1269,7 +1269,7 @@ std::vector<int> Game_Map::GetEncountersAt(int x, int y) {
 			return false;
 		}
 
-		const std::vector<bool>& terrain_set = troop->terrain_set;
+		const auto& terrain_set = troop->terrain_set;
 
 		// RPG_RT optimisation: Omitted entries are the default value (true)
 		return terrain_set.size() <= (unsigned)(terrain_tag - 1) ||