This simplistic arcade shooter will leave with plenty to do and lots of $$$ left in your pocket.
That being said, Onslaught is a solid addition to the WiiWare library. As a FPS addict, I perked up when I saw that a multiplayer FPS was available from WiiWare. After downloading it and kicking it up, I was actually disappointed from the text advanced story. It wasn't very intriguing and didn't improve. I was worried early with the lack of plot, or presentation of it.
Things improved immensely when I started the first single player mission. The gameplay was simple, yet arcade-ish from the beginning. The player gets points for kills, and can develop combos by combining kills. This combined with time used to complete a level and health remaining all add up into the final level score, adding a level of replay value that makes up for the light gameplay.
There are 4 basic guns you can use: a burst-mode longer range rifle, a machine gun, a shotgun and a rocket launcher. In addition there are grenades (thrown by activating their button and making a throwing motion with the nunchuk) and a laser whip, which satisfies the melee requirement. All of these except the whip can be upgraded 3 times with improved power, ammo and shooting speed, or a combo of the three.
The single player game is short, around 10 levels or so. It's divided in such a way that every so often you can choose which mission to complete, but all of them must be completed. The story still is pathetic, but please tell me the last time I bought a FPS specifically for the plot.
Online is very fun, with a strange co-op only mode. You are set in this HUGE desert level with the other players, and have to kill anything and everything to compete for the highest scores. The game ends after 8:00 (?) minutes or when the boss in the middle has been reached and killed. It's lots of fun, and a good break from the typical deathmatch. It is something to be said about the player base or skill, however, that after only 2 matches I lay in the top 150 in America score-wise. Hmmm...
All in all, I recommend it heartily to anyone who enjoys a good fun shooter without wanting to be bogged down by heavy gameplay.