Games like Tower 21

"Northend Tower Defense" is a strategy game with big battles and smooth performance. Choose from over 20 unique units, each with their own abilities, and upgrade them as you progress through 8 different levels. Use skills as the commander to turn the tide of battle in your favor.

"Grim Nights" is a top-down, open-world survival game set in a post-apocalyptic world. Players must scavenge for resources, craft tools, and build shelters to survive against the harsh elements and dangerous enemies. The game also features a day-night cycle and dynamic weather system, adding to the survival challenges. However, please note that the game is currently in Early Access and may still have some bugs and unfinished features.

"Valeguard is a single-player Role Playing game that takes about 24 hours to beat. It is a Tower Defense and Town-Management hybrid, where you construct defenses, train troops, and prepare for battle during the day, and defend with towers, troops, and heroes at night. Each town you save unlocks unique assets and heroes for future battles, with the option to gather resources, craft weapons, and train troops to help with defense."

"Northend Open Tower Defense Battle" is a real-time Tower Defense game featuring 8 distinct soldier types with unique strengths and weaknesses, and future additions of vehicles and aircraft. Players can engage in large-scale battles on two levels, the desert and the beach, with over 40 upgrades available to enhance their chosen units based on the situation. The game is optimized for smooth performance despite the high number of units involved.

Fortress TD is a single-player strategy game set in an open-world zombie apocalypse, blending tower defense with survival tactics. Featuring a delightful story, stellar gameplay, and marvelous visuals, players must strategically build and defend fortresses against relentless zombie hordes. Its immersive design offers a thrilling mix of strategy and action.

In Toy Shire, your new toys have been abandoned by your family and seek revenge on your latest gifts. As the leader of the green soldier toys, you must strategically build defenses and troops to protect your new toys and fend off various enemies, some of which may not be your old playthings. Tower defense alone won't be enough; careful positioning and tactical attacks are crucial to your success.

REDCON is a steampunk-inspired artillery strategy game set in a never-ending World War I. Command your own fortress and choose enemy systems to target while balancing resources. Utilize Active Pause to issue multiple orders, deploy a vast weapons arsenal, and protect your fortress from intruders. Customize your battle fortress and choose your strategy: infiltration, annihilation, or attrition.

"Bad North: Jotunn Edition" is a real-time tactics roguelite where you defend your kingdom against Viking invaders on procedurally-generated islands. Command your troops to utilize the unique terrain of each island, with the goal of ensuring your people's survival in this charming but brutal game. Failure results in the blood of your subjects staining the ground, making every battle a desperate fight.

Protect & Defense: Tower Zone is a single-player strategy game where you build towers to defend against invading aliens and enemies like balloons. It features stunning game mechanics and good graphics that enhance the tactical experience. However, players may find the frequent ads disruptive during gameplay.

Cannon Heroes is a single-player role-playing game where you destroy enemies, master skills, and strive to win. While offering engaging gameplay, it suffers from too many advertisements and is often full of bugs, which can hinder the overall experience. Despite its flaws, it provides a challenging adventure for fans of the genre.