diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
index 93f3780..6b0be57 100644
--- a/.github/FUNDING.yml
+++ b/.github/FUNDING.yml
@@ -1,3 +1 @@
-# These are supported funding model platforms
-
-custom: https://www.paypal.me/hectormf
+custom: https://hector.molinero.dev/donate
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 018ca69..83f3181 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,38 +1,38 @@
-image: docker:stable
+image: "docker.io/docker:stable"
 
 services:
-  - docker:dind
+  - "docker:dind"
 
 stages:
-  - build:images
-  - push:images
+  - "build:images"
+  - "push:images"
 
 variables:
-  DOCKER_HOST: tcp://docker:2375
-  DOCKER_DRIVER: overlay2
+  DOCKER_HOST: "tcp://docker:2375"
+  DOCKER_DRIVER: "overlay2"
 
 build:image:
-  stage: build:images
+  stage: "build:images"
   before_script:
-    - docker info
-    - apk add --no-cache coreutils git make xz
+    - "docker info"
+    - "apk add --no-cache coreutils git make xz"
   script:
-    - make build-image save-image
+    - "make build-image save-image"
   artifacts:
-    expire_in: 1 hour
+    expire_in: "1 hour"
     paths:
-      - dist/
+      - "dist/"
 
 push:image:
-  stage: push:images
+  stage: "push:images"
   before_script:
-    - apk add --no-cache coreutils git make xz
-    - docker login -u "${CI_REGISTRY_USER}" -p "${CI_REGISTRY_PASSWORD}" "${CI_REGISTRY}" >/dev/null 2>&1
+    - "apk add --no-cache coreutils git make xz"
+    - "docker login -u \"${CI_REGISTRY_USER:?}\" -p \"${CI_REGISTRY_PASSWORD:?}\" \"${CI_REGISTRY:?}\" >/dev/null 2>&1"
   script:
-    - make load-image push-image
+    - "make load-image push-image"
   only:
-    - /^v([0-9.]+)(-.+)?$/
+    - "/^v([0-9.]+)(-.+)?$/"
   except:
-    - branches
+    - "branches"
   dependencies:
-    - build:image
+    - "build:image"
diff --git a/Dockerfile b/Dockerfile
index d064a63..7c6089d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -35,8 +35,8 @@ RUN mkdir -p /var/lib/qemu/images/ /var/lib/qemu/iso/
 ARG REACTOS_ISO_URL=https://downloads.sourceforge.net/project/reactos/ReactOS/0.4.11/ReactOS-0.4.11-iso.zip
 ARG REACTOS_ISO_CHECKSUM=68120b3481c99c6b0563d5f3ec469ab197f2c8abc38d29adba4c40d01acd92c8
 RUN mkdir /tmp/reactos/ \
-	&& curl -Lo /tmp/reactos/reactos.zip "${REACTOS_ISO_URL}" \
-	&& echo "${REACTOS_ISO_CHECKSUM}  /tmp/reactos/reactos.zip" | sha256sum -c \
+	&& curl -Lo /tmp/reactos/reactos.zip "${REACTOS_ISO_URL:?}" \
+	&& echo "${REACTOS_ISO_CHECKSUM:?}  /tmp/reactos/reactos.zip" | sha256sum -c \
 	&& unzip /tmp/reactos/reactos.zip -d /tmp/reactos/ \
 	&& mv /tmp/reactos/*.iso /var/lib/qemu/iso/reactos.iso \
 	&& rm -rf /tmp/reactos/
@@ -53,4 +53,4 @@ EXPOSE 5900/tcp
 ## noVNC
 EXPOSE 6080/tcp
 
-CMD ["/usr/local/bin/docker-foreground-cmd"]
+CMD ["/usr/local/bin/container-foreground-cmd"]
diff --git a/Makefile b/Makefile
index 6f7b3fb..ac6ee8e 100644
--- a/Makefile
+++ b/Makefile
@@ -93,9 +93,9 @@ push-image:
 version:
 	@if printf -- '%s' '$(IMAGE_VERSION)' | grep -q '^v[0-9]\{1,\}$$'; then \
 		NEW_IMAGE_VERSION=$$(awk -v 'v=$(IMAGE_VERSION)' 'BEGIN {printf "v%.0f", substr(v,2)+1}'); \
-		printf -- '%s\n' "$${NEW_IMAGE_VERSION}" > ./VERSION; \
-		'$(GIT)' add ./VERSION; '$(GIT)' commit -m "$${NEW_IMAGE_VERSION}"; \
-		'$(GIT)' tag -a "$${NEW_IMAGE_VERSION}" -m "$${NEW_IMAGE_VERSION}"; \
+		printf -- '%s\n' "$${NEW_IMAGE_VERSION:?}" > '$(VERSION_FILE)'; \
+		'$(GIT)' add '$(VERSION_FILE)'; '$(GIT)' commit -m "$${NEW_IMAGE_VERSION:?}"; \
+		'$(GIT)' tag -a "$${NEW_IMAGE_VERSION:?}" -m "$${NEW_IMAGE_VERSION:?}"; \
 	else \
 		>&2 printf -- 'Malformed version string: %s\n' '$(IMAGE_VERSION)'; \
 		exit 1; \
diff --git a/run.sh b/run.sh
index 33ccac4..600701b 100755
--- a/run.sh
+++ b/run.sh
@@ -3,42 +3,45 @@
 set -eu
 export LC_ALL=C
 
+DOCKER=$(command -v docker 2>/dev/null)
+
+IMAGE_REGISTRY=docker.io
 IMAGE_NAMESPACE=hectormolinero
 IMAGE_PROJECT=qemu-reactos
 IMAGE_TAG=latest
-IMAGE_NAME=${IMAGE_NAMESPACE}/${IMAGE_PROJECT}:${IMAGE_TAG}
-CONTAINER_NAME=${IMAGE_PROJECT}
+IMAGE_NAME=${IMAGE_REGISTRY:?}/${IMAGE_NAMESPACE:?}/${IMAGE_PROJECT:?}:${IMAGE_TAG:?}
+CONTAINER_NAME=${IMAGE_PROJECT:?}
 
-imageExists() { [ -n "$(docker images -q "$1")" ]; }
-containerExists() { docker ps -aqf name="$1" --format '{{.Names}}' | grep -Fxq "$1"; }
-containerIsRunning() { docker ps -qf name="$1" --format '{{.Names}}' | grep -Fxq "$1"; }
+imageExists() { [ -n "$("${DOCKER:?}" images -q "${1:?}")" ]; }
+containerExists() { "${DOCKER:?}" ps -af name="${1:?}" --format '{{.Names}}' | grep -Fxq "${1:?}"; }
+containerIsRunning() { "${DOCKER:?}" ps -f name="${1:?}" --format '{{.Names}}' | grep -Fxq "${1:?}"; }
 
-if ! imageExists "${IMAGE_NAME}"; then
-	>&2 printf -- '%s\n' "\"${IMAGE_NAME}\" image doesn't exist!"
+if ! imageExists "${IMAGE_NAME:?}" && ! imageExists "${IMAGE_NAME#docker.io/}"; then
+	>&2 printf -- '%s\n' "\"${IMAGE_NAME:?}\" image doesn't exist!"
 	exit 1
 fi
 
-if containerIsRunning "${CONTAINER_NAME}"; then
-	printf -- '%s\n' "Stopping \"${CONTAINER_NAME}\" container..."
-	docker stop "${CONTAINER_NAME}" >/dev/null
+if containerIsRunning "${CONTAINER_NAME:?}"; then
+	printf -- '%s\n' "Stopping \"${CONTAINER_NAME:?}\" container..."
+	"${DOCKER:?}" stop "${CONTAINER_NAME:?}" >/dev/null
 fi
 
-if containerExists "${CONTAINER_NAME}"; then
-	printf -- '%s\n' "Removing \"${CONTAINER_NAME}\" container..."
-	docker rm "${CONTAINER_NAME}" >/dev/null
+if containerExists "${CONTAINER_NAME:?}"; then
+	printf -- '%s\n' "Removing \"${CONTAINER_NAME:?}\" container..."
+	"${DOCKER:?}" rm "${CONTAINER_NAME:?}" >/dev/null
 fi
 
-printf -- '%s\n' "Creating \"${CONTAINER_NAME}\" container..."
-docker run --detach \
-	--name "${CONTAINER_NAME}" \
-	--hostname "${CONTAINER_NAME}" \
+printf -- '%s\n' "Creating \"${CONTAINER_NAME:?}\" container..."
+"${DOCKER:?}" run --detach \
+	--name "${CONTAINER_NAME:?}" \
+	--hostname "${CONTAINER_NAME:?}" \
 	--restart on-failure:3 \
 	--log-opt max-size=32m \
 	--publish '127.0.0.1:5900:5900/tcp' \
 	--publish '127.0.0.1:6080:6080/tcp' \
 	--publish '127.0.0.1:15900:15900/tcp' \
 	--privileged --env QEMU_KVM=true \
-	"${IMAGE_NAME}" "$@" >/dev/null
+	"${IMAGE_NAME:?}" "$@" >/dev/null
 
 printf -- '%s\n\n' 'Done!'
-exec docker logs -f "${CONTAINER_NAME}"
+exec "${DOCKER:?}" logs -f "${CONTAINER_NAME:?}"
diff --git a/scripts/bin/docker-foreground-cmd b/scripts/bin/container-foreground-cmd
similarity index 60%
rename from scripts/bin/docker-foreground-cmd
rename to scripts/bin/container-foreground-cmd
index 42492cf..9ab9051 100755
--- a/scripts/bin/docker-foreground-cmd
+++ b/scripts/bin/container-foreground-cmd
@@ -4,7 +4,7 @@ set -eu
 
 # Create ReactOS disk
 if [ ! -f /var/lib/qemu/images/reactos.img ]; then
-	qemu-img create -f "${QEMU_DISK_FORMAT}" /var/lib/qemu/images/reactos.img "${QEMU_DISK_SIZE}"
+	qemu-img create -f "${QEMU_DISK_FORMAT:?}" /var/lib/qemu/images/reactos.img "${QEMU_DISK_SIZE:?}"
 fi
 
 # Start all services
diff --git a/scripts/service/qemu/run b/scripts/service/qemu/run
index 10c5a99..0c1a5d8 100755
--- a/scripts/service/qemu/run
+++ b/scripts/service/qemu/run
@@ -3,16 +3,16 @@
 set -eu
 
 QEMU=$(command -v qemu-system-x86_64)
-QEMU_ARGS="${QEMU_ARGS-} -smp ${QEMU_CPU} -m ${QEMU_RAM}"
+QEMU_ARGS="${QEMU_ARGS-} -smp ${QEMU_CPU:?} -m ${QEMU_RAM:?}"
 QEMU_ARGS="${QEMU_ARGS-} -vga std -display vnc=:0"
-QEMU_ARGS="${QEMU_ARGS-} -drive file=/var/lib/qemu/images/reactos.img,index=0,media=disk,format=${QEMU_DISK_FORMAT}"
+QEMU_ARGS="${QEMU_ARGS-} -drive file=/var/lib/qemu/images/reactos.img,index=0,media=disk,format=${QEMU_DISK_FORMAT:?}"
 QEMU_ARGS="${QEMU_ARGS-} -drive file=/var/lib/qemu/iso/reactos.iso,index=2,media=cdrom,format=raw"
-QEMU_ARGS="${QEMU_ARGS-} -boot order=${QEMU_BOOT_ORDER},menu=${QEMU_BOOT_MENU},splash-time=5000"
-QEMU_ARGS="${QEMU_ARGS-} -netdev user,id=n0,${QEMU_NET_OPTIONS} -device ${QEMU_NET_DEVICE},netdev=n0"
+QEMU_ARGS="${QEMU_ARGS-} -boot order=${QEMU_BOOT_ORDER:?},menu=${QEMU_BOOT_MENU:?},splash-time=5000"
+QEMU_ARGS="${QEMU_ARGS-} -netdev user,id=n0,${QEMU_NET_OPTIONS:?} -device ${QEMU_NET_DEVICE:?},netdev=n0"
 QEMU_ARGS="${QEMU_ARGS-} -usb -device usb-tablet"
-QEMU_ARGS="${QEMU_ARGS-} -k ${QEMU_KEYBOARD}"
-if [ "${QEMU_KVM}" = true ]; then QEMU_ARGS="${QEMU_ARGS-} -enable-kvm"; fi
+QEMU_ARGS="${QEMU_ARGS-} -k ${QEMU_KEYBOARD:?}"
+if [ "${QEMU_KVM:?}" = true ]; then QEMU_ARGS="${QEMU_ARGS-} -enable-kvm"; fi
 
 cd ~/
 exec 2>&1
-exec "${QEMU}" ${QEMU_ARGS}
+exec "${QEMU:?}" ${QEMU_ARGS:?}