How to play Sentinel online
Sentinel was made only for the light gun, which you plug into the left controller port and point at the TV screen. The emulator on this site does not emulate a light gun, and the manual describes no joystick controls. That means you can load the game here, but you cannot really play it. To play it properly you need a real Atari 2600 or 7800, the XG-1 gun and an old CRT television, because light guns do not work on modern flat screens.
- Return to the title screen: F12 (the console’s Reset switch)
- Pause and resume: press F2 (the TV type switch) twice
Gameplay
You play a scientist who invented the Sentinel, a pulsing orb that can absorb energy, and you use it to fight back against aliens invading Earth. The orb moves steadily across each alien landscape on its own. Your job is to shoot the enemies on the ground and in the air before they hit it. The orb soaks up energy from destroyed enemies, power pods and energy capsules, while enemy fire drains it, and too many hits destroy it. You start with four lives.
At the end of each world waits a power station guarded by an alien leader. The station repairs itself quickly, so you have to shoot fast to destroy it. Each of the four planets has more and faster enemies than the last, and after the fourth you face the single entity behind the invasion. If things get desperate, shoot the orb itself to fire a Super Shot that clears every enemy on the screen. You begin with three, and Energy Pods can give you more Super Shots and extra lives.
| Target | Points |
|---|---|
| Dish / Tube / Star | 10 / 20 / 30 |
| Satellite / Blob / Spike | 40 / 50 / 60 |
| Hover Craft / Probe / Mine | 70 / 80 / 90 |
| Bonus Pod | 10 |
| Medium Pyramid | 100 |
| Small Pyramid | 250 |
| Large Pyramid | mystery value, 10–500 |
| Big Alien | 50 per hit |
Tips
- Shoot the closest threat first. Distant enemies can wait; the ones about to reach the orb cannot.
- Save your Super Shots. Keep them for moments when the screen fills up, or for the power stations.
- Look for secret areas. The manual hints at unmarked hidden spots that give bonuses.
History
The XG-1 light gun was sold for Atari’s XE Game System and also works with the 2600 and 7800, but very few games were made for it. Its gameplay follows the idea of the arcade game Crossbow, where you also shoot threats to protect someone else rather than yourself. The only other 2600 light-gun game, Shooting Arcade, was never released. Reviewers have mostly been unkind to Sentinel, calling it repetitive and more of a novelty than a lasting game. A 7800 version with better graphics came out in Europe in 1991.
