If having Portal on NVIDIA's portable gaming powerhouse SHIELD wasn't good enough, well how about Half-Life 2? The Android-powered console is now home to Valve's infamous first-person shooter.
Better yet, the versions of Half-Life 2 and Portal on the NVIDIA SHIELD are "the full PC versions natively on Android". Considering it's a portable gaming handheld, that's quite the win for NVIDIA. You can grab both Portal and Half-Life 2 for the NVIDIA SHIELD for $9.99 each from the Google Play store.