diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2a4607a38..18ae73124 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -3,23 +3,29 @@
 # see https://hub.docker.com/_/gcc/
 image: gcc
 
+cache:
+  key: apt-cache
+  paths:
+  - apt-cache/
+
+before_script:
+  - export APT_CACHE_DIR=`pwd`/apt-cache && mkdir -pv $APT_CACHE_DIR
+  - apt-get update -yq 
+  - apt-get -o dir::cache::archives="$APT_CACHE_DIR" install -y cmake libboost-filesystem-dev libboost-program-options-dev libboost-system-dev libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libswresample-dev libsdl2-dev libqt4-dev libopenal-dev libopenscenegraph-3.4-dev libunshield-dev libtinyxml-dev
+# - apt-get install -y libmygui-dev libbullet-dev  # to be updated to latest below because stretch is too old
+  - curl http://ftp.us.debian.org/debian/pool/main/b/bullet/libbullet-dev_2.87+dfsg-2_amd64.deb -o libbullet-dev_2.87+dfsg-2_amd64.deb
+  - curl http://ftp.us.debian.org/debian/pool/main/b/bullet/libbullet2.87_2.87+dfsg-2_amd64.deb -o libbullet2.87_2.87+dfsg-2_amd64.deb
+  - curl http://ftp.us.debian.org/debian/pool/main/m/mygui/libmygui.openglplatform0debian1v5_3.2.2+dfsg-1_amd64.deb -o libmygui.openglplatform0debian1v5_3.2.2+dfsg-1_amd64.deb
+  - curl http://ftp.us.debian.org/debian/pool/main/m/mygui/libmyguiengine3debian1v5_3.2.2+dfsg-1_amd64.deb -o libmyguiengine3debian1v5_3.2.2+dfsg-1_amd64.deb
+  - curl http://ftp.us.debian.org/debian/pool/main/m/mygui/libmygui-dev_3.2.2+dfsg-1_amd64.deb -o libmygui-dev_3.2.2+dfsg-1_amd64.deb
+  - dpkg --ignore-depends=libmygui.ogreplatform0debian1v5 -i *.deb 
+
 build:
   stage: build
   script: 
     - nproc
-    - apt-get update
-    - apt-get install -y cmake libboost-filesystem-dev libboost-program-options-dev libboost-system-dev
-    - apt-get install -y libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libswresample-dev
-    - apt-get install -y libsdl2-dev libqt4-dev libopenal-dev libopenscenegraph-3.4-dev libunshield-dev libtinyxml-dev
-    - apt-get install -y libmygui-dev libbullet-dev  # to be updated to latest below because stretch is too old
-    - curl http://ftp.us.debian.org/debian/pool/main/b/bullet/libbullet-dev_2.87+dfsg-2_amd64.deb -o libbullet-dev_2.87+dfsg-2_amd64.deb
-    - curl http://ftp.us.debian.org/debian/pool/main/b/bullet/libbullet2.87_2.87+dfsg-2_amd64.deb -o libbullet2.87_2.87+dfsg-2_amd64.deb
-    - curl http://ftp.us.debian.org/debian/pool/main/m/mygui/libmygui.openglplatform0debian1v5_3.2.2+dfsg-1_amd64.deb -o libmygui.openglplatform0debian1v5_3.2.2+dfsg-1_amd64.deb
-    - curl http://ftp.us.debian.org/debian/pool/main/m/mygui/libmyguiengine3debian1v5_3.2.2+dfsg-1_amd64.deb -o libmyguiengine3debian1v5_3.2.2+dfsg-1_amd64.deb
-    - curl http://ftp.us.debian.org/debian/pool/main/m/mygui/libmygui-dev_3.2.2+dfsg-1_amd64.deb -o libmygui-dev_3.2.2+dfsg-1_amd64.deb
-    - dpkg --ignore-depends=libmygui.ogreplatform0debian1v5 -i *.deb 
-    - mkdir build; cd build; cmake ../
-    - make -j3
+    - mkdir build; cd build; cmake -DCMAKE_BUILD_TYPE=MinSizeRel ../
+    - make -j2
     - DESTDIR=artifacts make install
   artifacts:
     paths: