The problem with Thandor: The Invasion is that its lack of creativity extends into every single part of the game.
Real-time strategy games have undergone many significant improvements over the years. Different games have individually helped make advances in the genre, through their unique style, story, unit design, interface, or multiplayer features - or even with some or all of these at the same time. Some exceptional real-time strategy games from several years ago, such as Starcraft and Total Annihilation, are still enjoyable even today. You'd think that with such a rich tradition to build on, game designers working on new real-time strategy games would almost instinctively gravitate to game elements that work well and discard those that don't. Unfortunately, that's not the case with Thandor: The Invasion, a forgettable real-time strategy game that has practically nothing to offer.
The story behind Thandor: The Invasion revolves around the reconstruction of the Alliances of Avares, and it is completely forgettable and irrelevant. This fact by itself doesn't condemn it: Total Annihilation is a perfect example of a game that has a negligible backstory but nevertheless has such good gameplay that it has become a classic in the genre. The problem with Thandor: The Invasion is that its lack of creativity extends into every single part of the game. Even after days of play, you'll still need to refer to the manual to remind you that the two resources in the game are xenite (for building) and tritium (for power). The 3D terrain engine is decent, but it still suffers because of the drab and uninspired artwork throughout the game. The game's few graphical details, such as how your units leave imprints in the ground or how they can knock down trees, are only interesting on first impression. The unit graphics are clean but unremarkable, and many of the units look the same. The enemy units are just mirror images of your units. In short, there's absolutely nothing in Thandor to draw you into the game. If you take the plunge anyway, you'll encounter another set of problems that affect how the game plays.
Thandor: The Invasion allows for build queues and waypoint movement but neglects to include any kind of unit formation options. What's worse is that the unit pathfinding and the computer's artificial intelligence are also both lacking. The pathfinding is adequate until units get in each other's way, which is when accurate pathfinding is particularly important - and this is where it breaks down completely in Thandor. There is a slider for the difficulty of the game's artificial intelligence, which apparently only adjusts the degree to which the computer cheats, since at the highest setting it churns out units at unbelievable speed - although it's still quite beatable.
Thandor's graphics engine tries to use 3D to enhance the gameplay, by letting you zoom and rotate the isometric perspective at will. But as real-time strategy games like Force Commander have shown, having to adjust the zoom level during play can be a hindrance, and while the units may look prettier up close, it's impractical to play the game that way. In fact, the biggest problem with the camera view is that the farthest zoom still isn't quite back far enough, given the ranges of the units' weapons. In a real-time strategy game, the ability to zoom out properly is much more important than the ability to zoom in.
Units and buildings can be upgraded through research, and investment in things like improved armor and range can give weaker units considerably more punch. New structures can be researched and built, and this makes new units available throughout the game. But since none of the units are very interesting to begin with, it's difficult to get excited about this. There is only one single-player campaign, and it's very short. The individual maps are uninteresting, and the gameplay is entirely linear. There are several multiplayer campaigns, and a perfunctory diplomacy function in the multiplayer mode, where you can make and break alliances, but the basic gameplay remains the same. The game has some minor technical problems, such as how it autodetects your graphics driver, but it doesn't choose it as the default setting when you first start the game. If you experience constant crashes to the desktop, you should make sure that you have not mistakenly selected the default glide mode, if you aren't using a 3dfx video card.
In a genre that has had some truly groundbreaking games in the last couple of years, Thandor: The Invasion doesn't even bother to borrow the best features of those games. Instead, it omits some basic conventions and has a totally uninspired presentation. It's really not worthwhile unless you've played every other real-time strategy game available and need another fix.