App Review: Sentinel Puts Fieldrunners on Notice
Sentinel by Origin8 is a great tower defense game worthy of competing with Tap Defense and Fieldrunners. The game takes place in the year 2029. Mankind has established a mining colony on Mars. However, after only 2 short years in operation, a distress call is sent back to Earth. The message cannot be read except for the word “invasion.” You are commander of the ship Sentinel, which is sent to Mars to help. Once you arrive, you must help defend the colony from the alien invaders. When you launch the game, this story is told to you with scrolling script in similar a style to Star Wars. At once, you can see that the graphics are great and the music fits the game very well.
Sentinel, like many other tower defense games has a fixed path that the enemy attackers follow. However, there are 3 different maps, 2 different battle modes, and 4 difficulty levels. Only the first map and battle mode are unlocked in the beginning. To unlock the others, you must prove yourself by defeating the ones that you have. The two battle modes are Assault and Endurance. The main difference between the two is that Assault has a fixed number of waves of attackers, Endurance does not. The second and third maps have the added difficulty that there are two places on the map where the aliens enter. You must defend two different pathways. Your money is a very limited resource so be sure you only build as much as you need. The money that you save will accumulate interest at the end of each attack wave.
To defend your colony, you have the typical choice of 5 towers (laser, bomb, slow, beam, and sniper). The sniper tower is locked in the beginning. To place a tower on the screen simply drag it to the spot where you want it to be. As the game gets more and more difficult, you can upgrade your towers to make them stronger. The defense that Sentinel adds that I have not seen in other tower defense games is barriers. There are physical barriers in the way of your attackers. If they make it past all of your defense towers, they must still break down the barrier before they can invade your facility. These barriers are quite strong and are flanked by sniper towers. Sometimes they serve as a good place to trap your enemy and kill them. However, the enemy will break them down over time (Some more quickly than others). This is where the second unique trait of this game comes in; your repair drones.
Repair Drones are fairly expensive, but they automatically find weakened structures and repair them. They can help your barriers stand longer. If you have no repairs to do, the drones will mine for you to get more money that you can use to buy more towers. You can only have up to 3 repair drones, and sometimes even with three the repairs happen too slowly to keep up with the damage being done. Another feature that I found I really liked was that before each wave of enemy attackers, the app flashes on the screen what type of attacker is approaching. This warning gives you a chance to prepare and upgrade your defenses with those that work best against that particular attacker.
Sentinel is a very well designed game that is quite challenging. It is a lot of fun to play and has lots of options to keep you coming back for more.
Sentinel is $4.99 in the iTunes App Store.
Sentinel Lite is free in the iTunes App Store. (This free version lacks Endurance Mode, some of the maps and structures, and the ability to compete with the online scoring system.)
Developer Website: www.origin8.com