In Sentinel SG-23, you are the defender of the portal and the only one who can protect it from enemy intrusions, strategizing smartly and placing your defenses wisely.

As you progress, the number of enemies increases and so does the difficulty. But don't worry, you'll have access to new defenses, each one more powerful and more impressive than the last, and you'll be able to perform improvements on existing defenses, making them more powerful and effective.

-Campaign Mode: Progress through a series of challenging levels. Each level is designed to test your strategy and defense skills. As you progress through the campaign, enemies become more difficult to face, and you'll need to adapt and improve your strategy in order to progress. Completing each level will reward you with energy points that can be used to improve your defenses.

-Adventure Mode: Survive for as many attacks as you can.
With each new wave of enemies, you must build your defenses and prepare for the next invasion. With each wave, enemies become stronger, and your defenses need to be improved to keep up with the increase in enemy attack power. Try to beat your own record, survive long enough and be rewarded with energy points to upgrade your defenses.