This is one of my favorite obscure arcade games, and this 5200 implementation is nearly perfect. The look, feel, and sound of the arcade are as closely implemented as possible. I wish they'd had some way to implement the 4-button firing scheme of the arcade controls, but doing so would have been awkward as it would have required the use of the keypad. Still, the compromise offered is good, and the game play doesn't suffer much because of it.
If you're like me and enjoy Vanguard at the arcade, get this one!