diff --git a/src/editor/app.zig b/src/editor/app.zig
index 1445c1d0..eff2201d 100755
--- a/src/editor/app.zig
+++ b/src/editor/app.zig
@@ -4,7 +4,8 @@ const core = mach.core;
 const gpu = mach.gpu;
 
 pub const name = .editor;
-pub const App = mach.App(.{ mach.Module, @This() });
+pub const modules = .{ mach.Module, @This() };
+pub const App = mach.App;
 
 const UniformBufferObject = struct {
     resolution: @Vector(2, f32),
@@ -24,8 +25,8 @@ fragment_shader_file: std.fs.File,
 fragment_shader_code: [:0]const u8,
 last_mtime: i128,
 
-pub fn init(adapter: anytype) !void {
-    var editor = adapter.mod(.editor).state();
+pub fn init(eng: *mach.Engine) !void {
+    var editor = eng.mod(.editor).state();
 
     core.setTitle("Mach editor");
 
@@ -82,8 +83,8 @@ pub fn init(adapter: anytype) !void {
     bgl.release();
 }
 
-pub fn deinit(adapter: anytype) !void {
-    var editor = adapter.mod(.editor).state();
+pub fn deinit(eng: *mach.Engine) !void {
+    var editor = eng.mod(.editor).state();
     defer _ = gpa.deinit();
 
     editor.fragment_shader_file.close();
@@ -93,16 +94,16 @@ pub fn deinit(adapter: anytype) !void {
     editor.bind_group.release();
 }
 
-pub fn tick(adapter: anytype) !void {
-    var editor = adapter.mod(.editor).state();
+pub fn tick(eng: *mach.Engine) !void {
+    var editor = eng.mod(.editor).state();
 
     var iter = core.pollEvents();
     while (iter.next()) |event| {
         switch (event) {
             .key_press => |ev| {
-                if (ev.key == .space) return adapter.send(.machExit);
+                if (ev.key == .space) return eng.send(.machExit);
             },
-            .close => return adapter.send(.machExit),
+            .close => return eng.send(.machExit),
             else => {},
         }
     }
@@ -114,7 +115,7 @@ pub fn tick(adapter: anytype) !void {
             editor.fragment_shader_file.seekTo(0) catch unreachable;
             editor.fragment_shader_code = editor.fragment_shader_file.readToEndAllocOptions(allocator, std.math.maxInt(u32), null, 1, 0) catch |err| {
                 std.log.err("Err: {}", .{err});
-                return adapter.send(.machExit);
+                return eng.send(.machExit);
             };
             editor.pipeline = recreatePipeline(editor.fragment_shader_code, null);
         }
diff --git a/src/editor/main.zig b/src/editor/main.zig
index c5058d9d..a9b51fc8 100644
--- a/src/editor/main.zig
+++ b/src/editor/main.zig
@@ -8,6 +8,8 @@ comptime {
 const std = @import("std");
 const builtin = @import("builtin");
 
+// Forward "app" declarations into our namespace, such that @import("root").foo works as expected.
+pub usingnamespace @import("app");
 const App = @import("app").App;
 const core = @import("core");
 const gpu = core.gpu;
diff --git a/src/engine.zig b/src/engine.zig
index f7ed9974..0c24ee2b 100644
--- a/src/engine.zig
+++ b/src/engine.zig
@@ -13,47 +13,61 @@ pub const Module = struct {
 
     pub const name = .mach;
 
-    pub fn machInit(adapter: anytype) !void {
-        var mach = adapter.mod(.mach);
+    pub fn machInit(eng: *Engine) !void {
+        var mach = eng.mod(.mach);
 
         core.allocator = allocator;
         try core.init(.{});
         mach.state().device = core.device;
         mach.state().exit = false;
 
-        try adapter.send(.init);
+        try eng.send(.init);
     }
 
-    pub fn machDeinit(adapter: anytype) !void {
-        try adapter.send(.deinit);
+    pub fn machDeinit(eng: *Engine) !void {
+        try eng.send(.deinit);
         core.deinit();
-        adapter.deinit();
+        eng.deinit();
         _ = gpa.deinit();
     }
 
-    pub fn machExit(adapter: anytype) !void {
-        try adapter.send(.exit);
-        var state = adapter.mod(.mach).state();
+    pub fn machExit(eng: *Engine) !void {
+        try eng.send(.exit);
+        var state = eng.mod(.mach).state();
         state.exit = true;
     }
 };
 
-pub fn App(comptime modules: anytype) type {
-    return struct {
-        engine: ecs.World(modules),
+pub const App = struct {
+    engine: Engine,
 
-        pub fn init(app: *@This()) !void {
-            app.* = .{ .engine = try ecs.World(modules).init(allocator) };
-            try app.engine.send(.machInit);
-        }
+    pub fn init(app: *@This()) !void {
+        app.* = .{ .engine = try Engine.init(allocator) };
+        try app.engine.send(.machInit);
+    }
 
-        pub fn deinit(app: *@This()) void {
-            try app.engine.send(.machDeinit);
-        }
+    pub fn deinit(app: *@This()) void {
+        try app.engine.send(.machDeinit);
+    }
 
-        pub fn update(app: *@This()) !bool {
-            try app.engine.send(.tick);
-            return app.engine.mod(.mach).state().exit;
-        }
-    };
+    pub fn update(app: *@This()) !bool {
+        try app.engine.send(.tick);
+        return app.engine.mod(.mach).state().exit;
+    }
+};
+
+pub const Engine = ecs.World(modules());
+
+fn Modules() type {
+    if (!@hasDecl(@import("root"), "modules")) {
+        @compileError("expected `pub const modules = .{};` in root file");
+    }
+    return @TypeOf(@import("root").modules);
+}
+
+fn modules() Modules() {
+    if (!@hasDecl(@import("root"), "modules")) {
+        @compileError("expected `pub const modules = .{};` in root file");
+    }
+    return @import("root").modules;
 }
diff --git a/src/gfx2d/Sprite2D.zig b/src/gfx2d/Sprite2D.zig
index e7f20b61..05099daf 100644
--- a/src/gfx2d/Sprite2D.zig
+++ b/src/gfx2d/Sprite2D.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 const core = @import("core");
 const gpu = core.gpu;
 const ecs = @import("ecs");
+const Engine = @import("../engine.zig").Engine;
 
 const math = @import("../math.zig");
 const mat = math.mat;
@@ -52,9 +53,9 @@ const Uniforms = extern struct {
     texture_size: Vec2 align(16),
 };
 
-pub fn machSprite2DInit(adapter: anytype) !void {
-    var mach = adapter.mod(.mach);
-    var sprite2d = adapter.mod(.mach_sprite2d);
+pub fn machSprite2DInit(eng: *Engine) !void {
+    var mach = eng.mod(.mach);
+    var sprite2d = eng.mod(.mach_sprite2d);
     const device = mach.state().device;
 
     const uniform_buffer = device.createBuffer(&.{
@@ -70,7 +71,7 @@ pub fn machSprite2DInit(adapter: anytype) !void {
         .min_filter = .nearest,
     });
 
-    const sprite_buffer_cap = 1024 * 128; // TODO: allow user to specify preallocation
+    const sprite_buffer_cap = 1024 * 256; // TODO: allow user to specify preallocation
     const sprite_transforms = device.createBuffer(&.{
         .usage = .{ .storage = true, .copy_dst = true },
         .size = @sizeOf(Mat4x4) * sprite_buffer_cap,
@@ -156,8 +157,8 @@ pub fn machSprite2DInit(adapter: anytype) !void {
     shader_module.release();
 }
 
-pub fn deinit(adapter: anytype) !void {
-    var sprite2d = adapter.mod(.mach_sprite2d);
+pub fn deinit(eng: *Engine) !void {
+    var sprite2d = eng.mod(.mach_sprite2d);
 
     sprite2d.state().texture.release();
     sprite2d.state().pipeline.release();
@@ -169,9 +170,9 @@ pub fn deinit(adapter: anytype) !void {
     sprite2d.state().sprite_sizes.release();
 }
 
-pub fn tick(adapter: anytype) !void {
-    var mach = adapter.mod(.mach);
-    var sprite2d = adapter.mod(.mach_sprite2d);
+pub fn tick(eng: *Engine) !void {
+    var mach = eng.mod(.mach);
+    var sprite2d = eng.mod(.mach_sprite2d);
     const device = mach.state().device;
 
     // Begin our render pass
@@ -204,7 +205,7 @@ pub fn tick(adapter: anytype) !void {
     encoder.writeBuffer(sprite2d.state().uniform_buffer, 0, &[_]Uniforms{uniforms});
 
     // Synchronize entity data into our GPU sprite buffer
-    var archetypes_iter = adapter.entities.query(.{ .all = &.{
+    var archetypes_iter = eng.entities.query(.{ .all = &.{
         .{ .mach_sprite2d = &.{
             .uv_transform,
             .transform,
@@ -213,20 +214,20 @@ pub fn tick(adapter: anytype) !void {
     } });
 
     // TODO: eliminate these
-    var sprite_transforms = try std.ArrayListUnmanaged(Mat4x4).initCapacity(adapter.allocator, 1000);
-    defer sprite_transforms.deinit(adapter.allocator);
-    var sprite_uv_transforms = try std.ArrayListUnmanaged(Mat3x3).initCapacity(adapter.allocator, 1000);
-    defer sprite_uv_transforms.deinit(adapter.allocator);
-    var sprite_sizes = try std.ArrayListUnmanaged(Vec2).initCapacity(adapter.allocator, 1000);
-    defer sprite_sizes.deinit(adapter.allocator);
+    var sprite_transforms = try std.ArrayListUnmanaged(Mat4x4).initCapacity(eng.allocator, 1000);
+    defer sprite_transforms.deinit(eng.allocator);
+    var sprite_uv_transforms = try std.ArrayListUnmanaged(Mat3x3).initCapacity(eng.allocator, 1000);
+    defer sprite_uv_transforms.deinit(eng.allocator);
+    var sprite_sizes = try std.ArrayListUnmanaged(Vec2).initCapacity(eng.allocator, 1000);
+    defer sprite_sizes.deinit(eng.allocator);
     while (archetypes_iter.next()) |archetype| {
         var transforms = archetype.slice(.mach_sprite2d, .transform);
         var uv_transforms = archetype.slice(.mach_sprite2d, .uv_transform);
         var sizes = archetype.slice(.mach_sprite2d, .size);
         for (transforms, uv_transforms, sizes) |transform, uv_transform, size| {
-            try sprite_transforms.append(adapter.allocator, transform);
-            try sprite_uv_transforms.append(adapter.allocator, uv_transform);
-            try sprite_sizes.append(adapter.allocator, size);
+            try sprite_transforms.append(eng.allocator, transform);
+            try sprite_uv_transforms.append(eng.allocator, uv_transform);
+            try sprite_sizes.append(eng.allocator, size);
         }
     }
     const total_vertices = @as(u32, @intCast(sprite_sizes.items.len * 6));
diff --git a/src/main.zig b/src/main.zig
index 8ea6c688..10fd1ee3 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -20,6 +20,7 @@ pub const Atlas = @import("atlas/Atlas.zig");
 // Engine exports
 pub const App = @import("engine.zig").App;
 pub const Module = @import("engine.zig").Module;
+pub const Engine = @import("engine.zig").Engine;
 
 const std = @import("std");