The short version: this is a good game. You should go play it. Well-worth paying full price ($30).
The long version: if you liked the original, you will like this. It’s basically the same game. Sure, the graphics are modernized, it’s got keyboard+mouse support, and even has a new mission (it’s a cut mission from the original files that’s been restored), but it’s the same game. They even used the same audio, so it keeps the humor that’s not allowed anymore (there is one line that’s taken out).
You might notice that it doesn’t quite look the same as before, besides the improved graphics and textures. The devs for the remake thought that these cartoony characters worked better for the tone of the game than the original’s more idealized depictions. I don’t really agree, but it’s a minor thing.
For those of you who haven’t played the original, this is a third-person shooter in the classic style. Meaning, this isn’t a cover shooter, there are no real stealth elements, you just go around shooting things. Well, you do more than that – since you have no stealth, you do your non-shooty bits by taking the holographic form of various humans. You can read their minds, which can give mission hints, but mostly they’re just fun (this also recharges your holographic disguise). You can pick up and throw things with your mind. You have a few different weapons (including an anal probe that causes heads to explode). You have a jet pack to do jet pack things. You also have a flying saucer to do more enhanced destruction.
Between missions you can upgrade all this stuff with the DNA currency that you collect. Which you mostly get by stealing people’s brains (thus the anal probe causing exploding heads). There are also hidden alien probes around the maps that also give you DNA. Every map can be revisited after/between missions to gather all the collectibles and do minigames so you can upgrade your stuff. (You can also just plain replay missions, to get optional objectives or whatever.) The game is pretty easy overall, but it’s the upgrades that make it so. (And you’re going to really want those upgrades for the few difficult parts of the game.)
I personally have played a bit over 13 hours to this point. In this time I did all the main missions, and have replayed several of the maps. I haven’t 100% any of them though. I’d really have to get a guide to find the last of the probes on some of those maps. But for now, I’m satisfied. The replayability is a major part of this game – sometimes you just have a need to destroy a town, and you can do that as many times as you want. I really hope this game is such a success that THQ decides to remake the sequel, which is an even better game than this one.