diff --git a/deps/nostalgia/src/olympic/turbine/include/turbine/turbine.hpp b/deps/nostalgia/src/olympic/turbine/include/turbine/turbine.hpp
index f12b18e..d24897b 100644
--- a/deps/nostalgia/src/olympic/turbine/include/turbine/turbine.hpp
+++ b/deps/nostalgia/src/olympic/turbine/include/turbine/turbine.hpp
@@ -14,6 +14,8 @@
 
 namespace turbine {
 
+using TimeMs = uint64_t;
+
 ox::Result<ContextUPtr> init(ox::UPtr<ox::FileSystem> &&fs, ox::CRStringView appName) noexcept;
 
 ox::Error run(Context &ctx) noexcept;
@@ -21,7 +23,7 @@ ox::Error run(Context &ctx) noexcept;
 // Returns the number of milliseconds that have passed since the start of the
 // program.
 [[nodiscard]]
-uint64_t ticksMs(Context const&ctx) noexcept;
+TimeMs ticksMs(Context const&ctx) noexcept;
 
 void requestShutdown(Context &ctx) noexcept;
 
diff --git a/deps/nostalgia/src/olympic/turbine/src/gba/turbine.cpp b/deps/nostalgia/src/olympic/turbine/src/gba/turbine.cpp
index aed5fb5..96432a2 100644
--- a/deps/nostalgia/src/olympic/turbine/src/gba/turbine.cpp
+++ b/deps/nostalgia/src/olympic/turbine/src/gba/turbine.cpp
@@ -8,6 +8,7 @@
 #include <keel/keel.hpp>
 #include <turbine/context.hpp>
 #include <turbine/gfx.hpp>
+#include <turbine/turbine.hpp>
 
 #include "context.hpp"
 #include "turbine.hpp"
@@ -71,7 +72,7 @@ ox::Result<ContextUPtr> init(
 void shutdown(Context&) noexcept {
 }
 
-uint64_t ticksMs(Context const&) noexcept {
+TimeMs ticksMs(Context const&) noexcept {
 	return g_timerMs;
 }
 
diff --git a/deps/nostalgia/src/olympic/turbine/src/glfw/context.hpp b/deps/nostalgia/src/olympic/turbine/src/glfw/context.hpp
index 6a6cd1d..8e20896 100644
--- a/deps/nostalgia/src/olympic/turbine/src/glfw/context.hpp
+++ b/deps/nostalgia/src/olympic/turbine/src/glfw/context.hpp
@@ -8,6 +8,7 @@
 #include <turbine/context.hpp>
 #include <turbine/gfx.hpp>
 #include <turbine/event.hpp>
+#include <turbine/turbine.hpp>
 
 namespace turbine {
 
@@ -24,7 +25,7 @@ class Context {
 		struct GLFWwindow *window = nullptr;
 		int refreshWithinMs = 0;
 		ox::Vector<gl::Drawer*, 5> drawers;
-		int64_t startTime = 0;
+		TimeMs startTime = 0;
 		uint64_t wakeupTime = 0;
 		uint64_t keysDown = 0;
 		uint64_t prevFpsCheckTime = 0;
diff --git a/deps/nostalgia/src/olympic/turbine/src/glfw/turbine.cpp b/deps/nostalgia/src/olympic/turbine/src/glfw/turbine.cpp
index 2865423..4ad5d26 100644
--- a/deps/nostalgia/src/olympic/turbine/src/glfw/turbine.cpp
+++ b/deps/nostalgia/src/olympic/turbine/src/glfw/turbine.cpp
@@ -45,7 +45,8 @@ ox::Result<ContextUPtr> init(
 	auto ctx = ox::make_unique<Context>();
 	oxReturnError(keel::init(ctx->keelCtx, std::move(fs), appName));
 	using namespace std::chrono;
-	ctx->startTime = duration_cast<milliseconds>(system_clock::now().time_since_epoch()).count();
+	ctx->startTime = static_cast<TimeMs>(
+			duration_cast<milliseconds>(system_clock::now().time_since_epoch()).count());
 	glfwInit();
 	oxReturnError(initGfx(*ctx));
 	glfwSetWindowSizeCallback(ctx->window, draw);
@@ -108,10 +109,10 @@ void shutdown(Context &ctx) noexcept {
 	}
 }
 
-uint64_t ticksMs(Context const&ctx) noexcept {
+TimeMs ticksMs(Context const&ctx) noexcept {
 	using namespace std::chrono;
 	auto const now = duration_cast<milliseconds>(system_clock::now().time_since_epoch()).count();
-	return static_cast<uint64_t>(now - ctx.startTime);
+	return static_cast<TimeMs>(now) - ctx.startTime;
 }
 
 bool buttonDown(Context const&ctx, Key key) noexcept {