diff --git a/package/ci/circleci.yml b/package/ci/circleci.yml
index 7b900fc57..7abddeeaf 100644
--- a/package/ci/circleci.yml
+++ b/package/ci/circleci.yml
@@ -637,7 +637,9 @@ jobs:
       TARGET_GLES2: "ON"
     steps:
     - install-base-linux
-    - cap-ninja-jobs
+    # With a Debug build, 16+ is causing OOMs. Release was fine with 24.
+    - cap-ninja-jobs:
+        count: 8
     - build:
         script: emscripten.sh
 
@@ -648,7 +650,9 @@ jobs:
       TARGET_GLES2: "OFF"
     steps:
     - install-base-linux
-    - cap-ninja-jobs
+    # With a Debug build, 8+ is causing OOMs. Release was fine with 24.
+    - cap-ninja-jobs:
+        count: 4
     - build:
         script: emscripten.sh
 
diff --git a/package/ci/emscripten.sh b/package/ci/emscripten.sh
index 8062283ff..297e8b591 100755
--- a/package/ci/emscripten.sh
+++ b/package/ci/emscripten.sh
@@ -9,9 +9,7 @@ cd corrade
 mkdir build-emscripten && cd build-emscripten
 cmake .. \
     -DCMAKE_TOOLCHAIN_FILE="../../toolchains/generic/Emscripten-wasm.cmake" \
-    -DCMAKE_BUILD_TYPE=Release \
-    -DCMAKE_CXX_FLAGS_RELEASE="-DNDEBUG -O1" \
-    -DCMAKE_EXE_LINKER_FLAGS_RELEASE="-O1" \
+    -DCMAKE_BUILD_TYPE=Debug \
     -DCMAKE_INSTALL_PREFIX=$HOME/deps \
     -DCORRADE_WITH_INTERCONNECT=OFF \
     -G Ninja
@@ -24,9 +22,7 @@ cd ..
 mkdir build-emscripten && cd build-emscripten
 cmake .. \
     -DCMAKE_TOOLCHAIN_FILE="../toolchains/generic/Emscripten-wasm.cmake" \
-    -DCMAKE_BUILD_TYPE=Release \
-    -DCMAKE_CXX_FLAGS_RELEASE="-DNDEBUG -O1" \
-    -DCMAKE_EXE_LINKER_FLAGS_RELEASE="-O1" \
+    -DCMAKE_BUILD_TYPE=Debug \
     -DCMAKE_INSTALL_PREFIX=$HOME/deps \
     -DCMAKE_FIND_ROOT_PATH=$HOME/deps \
     -DMAGNUM_WITH_AUDIO=ON \