Defense Grid is getting some new downloadable (paid) content today. Now, Defense Grid is not a well known or particularly heralded computer game. THis is a pity. Because Defense Grid is actually really rather good.
Available on the PC through the Steam delivery platform, and on the XBox through XBox Live (I believe), Defense Grid is a tower defence game where you build towers in a series of build platforms (you are limited to where you can place them, but you can choose which of the platforms you utilise) to kill aliens who are trying to steal power cores from a power plant.
This is all very standard, but it is the quality of execution that rises Defense Grid into a game I really recommend. The graphics are all of a piece and attractive enough (although sadly won’t run on very old graphics cards) and the aliens design allows them to look distinct. More than this, however, the aliens are genuinely distinct: they have different strengths and weaknesses, different attributes and require different approaches.
This is the second place where Defense Grid really raises its level: you have different towers with very different capabilities which you can upgrade several times. Some towers help you to afford further towers, some only attack flying aliens, some slow aliens down, some only attack ground aliens, some are better with groups and some are better against solo enemies.
A lot of thought has obviously been expended on making sure there is a lot of variety in the game and that the player can’t complete it by adopting a single strategy. Different levels require different combinations of towers, built in different orders. They also require towers built in different places, which is often something you discover through experimentation. Luckily, there are a series of save points on each level so you can go back to a previous save rather than having to start the level from scratch as you experiment.
There are also a variety of game modes, from the straightforward, to placing limits on you in terms of how many towers you can have, which you can have, by increasing the strength or amount of enemies or reversing the direction the enemies come from. This, coupled with a series of achievements for killing enemies, doing so efficiently, using different combinations or levels of towers and myriad other metrics give the game a replayability and make it excellent value for money.