I have just tested the installation process, and it worked fine for me:
cd
sudo rm -rf /usr/google/appinventor
sudo rm -rf ~/.appinventor
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install lib32z1
sudo apt-get install lib32stdc++6 >> "latest version already installed"
cd Downloads
sudo dpkg -i appinventor2-setup_2.3_all.deb
cd
/usr/google/appinventor/commands-for-Appinventor/aiStarter &
Both emulator and device via USB worked