Sanctum 2 is a game that combines tower defense gameplay into a first-person shooter. The combination works mostly well, but there are a few shortcomings here and there.

In terms of gameplay, each level/map in Sanctum 2 has one or more 'cores' which you have to defend from alien enemies. These enemies attack in waves, and there are two phases for each wave. In the planning phase, you build towers and walls. Walls are used to channel enemies into specific paths. Towers come in various forms, and they are used to attack the enemies. Different towers have different characteristics (damage, speed & range) and are appropriate for different types of enemies. The second phase of each wave is the actual attack phase. As enemies arrive, you can jump into the fray with a limited selection of weapons. More weapons and special abilities (perks) can be unlocked as you play.

Sanctum 2 succeeds in meshing these components into a cohesive whole. You typically need to deal with large numbers of enemies, so a pure FPS approach is not viable. From the other side, certain enemies tend to be resistant to damage, and most enemies are bullet sponges to some extent. So, a pure TD approach will not work as well. You have to work in tandem with your towers to keep enemies away from the core.

Beyond the gameplay, Sanctum 2 is built as a co-op multiplayer game. You can play solo, but the experience is clearly intended for multiplayer. During my solo playthrough, I was quickly overwhelmed by enemies, even in the earlier levels. I had to switch to easy mode to make the game more manageable.

The presentation of Sanctum 2 is adequate. Characters have an animated look to them. Environments are nice, and there is a fair bit of variation across maps. Enemies are appropriately creepy.

Over the course of the campaign, Sanctum 2 had a few unique obstacles to challenge me. The later maps are fairly unique in their design, and you have to come up with different strategies to deal with each one. This lends a puzzle element to the game, which I appreciated.

There is a story told through the campaign of Sanctum 2, but this seems like an afterthought. It is extremely predictable, and is told through a limited number of comic book panels (and no voice acting). This ties into the multiplayer focus that I mentioned previously.

I also think the FPS side could have used some more polish. The main problem is how the enemies are bullet sponges, so it takes ridiculous amounts of firepower to bring down some of the heavier enemies. Easy mode definitely brings this down to more reasonable levels.

In summary, I was entertained by Sanctum 2's unique approach to gameplay and its puzzle elements. As a solo player, the game was not very accessible until I turned on easy mode. I made it to the end of the campaign, and faced some clever challenges along the way.