Seeing as "Galaga" on the NES is 500 Wii points, this is by far a much better deal for 600 Wii points...
Unless your gaming-experience only started in the new millennium, you might not know too much about Galaxian/Galaga's legacy. Although virtually a "Space-invaders" clone with a bit of tweaking (moving enemies for one), the original Galaga is still revered as an important and enjoyable arcade-style shooter. It's most famous trait is arguably the ability to dock two fighters together. Yes, this was a big deal at the time! Of course, your fire-power and fire-coverage immediately doubles, but so does your size. And avoiding the falling enemies and their missiles becomes twice as difficult.
Thankfully, (and like all other TG16 games available), the standard Wiimote is compatible for Galaga '90, and the controls, like the premise and gameplay itself, are very simple. You move left and right with the D-pad, and button 1 or 2 fire. That's it. No special-move, no charging, no combo-moves, just move and shoot - this is about as simple as shooters get. However, even though there very little to learn, (in terms of gameplay mechanics themselves), you don't really feel under-prepared for your mission, as I will explain.
From the outset, you can choose if you wish to have two fighters docked from Stage 1. This is a great advantage and very alluring - I always give into to the temptation here. So, you can start out with double the fire-power, and wiping-out those hypnotically swirling enemies before they've even made their intricate formation is very satisfying, not to mention much easier than it would be if you were a single pilot.
Galaga '90 really added some new elements to the gameplay. As well as it's famous and trademark "Challenging Stages", now announced as "This is Galactic Dancing", we now have vertically-scrolling stages, as well as end-level bosses. Not to mention a modest amount of collecting and stage-warping. These improvements are quite refreshing, and add a bit more of a well-rounded shooter experience than "Galaga" or "Gaplus" might of.
The real improvement, the one that everyone would of been waiting for at the time, is the ability to triple your fire-power. Yes, triple! If you dock a ship to an already two-player ship, the whole bunch transform into a new kind of ship that has great power and the size of a double only. Getting this baby going is really satisfying - you can exterminate the aliens in record time with this things superior arsenal. When it does break-up (and believe me, it will), you feel so depleted and almost nervous. It is such a power-down that you can't believe you ever played Galaga without it.
Anyhow, this game is good for shooter fans as it is very challenging, not to mention that it is a unique addition to what was probably a series that was close to running out of ideas. It's the best in the series that I'm yet to play. Seeing as "Galaga" on the NES is 500 Wii points, this is by far a much better deal for 600 Wii points. The addition of different mission paths (a la "Starwing") is yet another factor that may excite high-score enthusiasts or maybe even speed-runners?