While it is indeed a classic, Galaga for the Xbox 360 lacks a distinct feature: a reason to keep playing.
Galaga retains what made the original fun. The game puts you in control of a ship, and your mission is to shoot and destroy the alien bugs that try to attack you. The game is simple, but the higher difficulty levels, in arcade tradition, are more addictive that the ones that precede them. It's a formula that worked in arcades for a while and has been used in many other games, but Galaga was one of the shooters that stood out. If you played the original, you'll be happy to know that the original game is fully intact, though some minor tweaks hurt the game's challenge.
Galaga adds a continue feature that lets you resume the game on the level where you died. This means that death is less of a factor in the game, so more casual players will be able to earn the games 200 acheivement points faster. Sadly, it also means the game's leaderboard feature is hardly as impressive as before, as any people who can persist long enough will be able to collect an enormous high score. The rapid fire button also means less button mashing, as well as less appeal for the hardcore. The Galaga fans will still enjoy this game, but these features will take away from the experience.
Also taking away from the experience is a miniscule feature set. The arcade game, a leaderoard, and 200 acheivements are all the gameplay options included in the game, which is quite frankly pathetic for a game you're expected to pay 5 dollars for. The very least Namco could've done is include a co-op multiplayer mode, time trials, or something that could add infinite value, but alas there is no such mode in the game. What it comes down to is that you'll be sick of the game in a day or two, which is just as disapointing as it sounds for a game this classic.
At least the game retains a memorable presentation. The graphics are exactly as the original game and a new, detailed background has been added to give the game an arcade cabinet style feel. The sound is essentially the same case, with the classic melody, bleeps and bloops in the original making their way into the game. From an aesthetic point of view, the game is a success.
A lot of the time, an XBLA retro game is reccomendable for those who remember and love the original. This really is not the case here. Galaga fans may enjoy the game for a few hours, but then they'll feel an emptyness that the game provides. Unless you need the 200 achievements, or need every XBLA game there is, you should probably take a pass on this one.