If you liked the retail version of Red Alert 3, this will certainly give you many more hours of gameplay.
It is disappointing they just didn't add the 'Uprising' campaign that PC gamers got, slap it on a disc and release it that way. Another disappointing thing is that there is no online multi-player whatsoever. There isn't even online CO-OP play, which was a huge part of the original retail release. In fact, there is no CO-OP play in the game at all and you are on your own in every mission. This wasn't a big deal to me, but I can see how it would bother a lot of people.
Other than those changes, along with the new units, this is essentially just more of the same. The catch here is that when you start the game, most of the 'tech' in the game is locked. As you complete missions, you unlock 'techs' for each faction. It's a fun way to do it, but it's nothing revolutionary. I didn't even use many of the new units due to them not being worth the cost or they just didn't fit how the mission should go. Some of them are quite fun, however. Wait until you see the 'Giga Fortress' in action.
One BIG annoyance I had with the game is the fact that you can't save mid-mission anymore. I am assuming this is due to the game trying to push you into beating each one under a 'par-time'. The problem is that some of the 'par-times' are ridiculously hard and most gamers will probably not get some of them regardless. Some of the missions are quite long & hard and it's frustrating to have to re-start after playing for 30 min. or longer. It would have been nice to have an option to save the game mid-mission and then have it cancel your 'par-time', for gamers who don't care how fast they beat the mission.
The game is also considerably harder than the retail 'Red Alert 3'. I know this is kinda the point, but there are some missions where you take on 2-3 other A.I. commanders and they all build twice as fast as you. While the controls didn't bother me much in the retail release, this is not the case with this expansion. Since the game is much more difficult, annoyances with the controls stick out WAY more than they did before. This actually reminds me of what I didn't like about the previous 'Command & Conquer' games for the Xbox 360 (the non-'Red Alert' ones). They didn't slow the game down from the PC release to give us console gamers a better chance since we don't have the ideal mouse/keyboard combo. For some reason, I didn't have this problem with the retail 'Red Alert 3'. But in 'Commander's Challenge', it rears it's ugly head in a big way. In the end, it's just REALLY hard & frustrating trying to keep up with 3 A.I. opponents with the increased difficulty.
So after all that, why would I recommend purchasing this game? Well, it is a lot of fun if you liked the original game. The problems I mentioned are very annoying, but none of them are game-killers. This game will probably frustrate you, but you will probably come back for more. I love the 'Red Alert' series, so this download was a no-brainer for me. If you are not a fan of this series, I would give the demo a shot or rent the original retail game first.
In the end, this is a great deal for $10 as you are getting A LOT of added content (and even a couple cheesy new cut-scenes) and it will keep you busy for many hours if you want it to. It's a huge download (at over 2 gigs) and the game looks just like the retail game. In fact, the presentation here is great for an XBLA game. This is not a must-have game for everyone. But for fans of the original or the 'Red Alert' series this is a fun & challenging game if you can look past some annoying quirks that are different than they retail 'Red Alert 3'.