Everything you need to defend your server — v3.0 Edition
You are the sysadmin. Your server sits at the center of the grid, and waves of cyber threats are closing in from all directions. Place defense towers, use special abilities, and click enemies to destroy them before they reach your server. Clear every wave to complete a level and advance. There are 100 levels to conquer, plus Endless Mode and Daily Challenges.
| Action | Mouse | Keyboard |
|---|---|---|
| Place tower | Click empty grid cell | Select type with 1–0, then click |
| Attack enemy | Click on enemy (sudo kill) | — |
| Select placed tower | Click on a tower | — |
| Sell tower | Right-click on tower | Sell button in panel |
| Pause / Resume | PAUSE button | P or ESC |
| Speed control | 1x/2x/3x buttons | — |
| Mute / Unmute | Mute button in HUD | M |
| Heal server | Ability button | R (Reboot) / B (Backup) |
| Overclock towers | Ability button | O |
| Kill all enemies | Ability button | SPACE |
CPU is your primary resource. You spend CPU to place towers, upgrade towers, and activate abilities. You earn CPU by killing enemies, clicking enemies manually (+2 CPU per click), passive generation (1 CPU/sec base, scales with level), and level completion bonuses.
Your server's health. When it reaches 0, the game is over (KERNEL PANIC). Enemies deal damage when they reach the server. Restore HP with System Reboot and Backup Restore abilities, or place Firewall+ towers that heal 2 HP/sec.
Select a tower type from the side panel (or press 1–0), then click an empty grid cell to place it. Each tower targets the nearest enemy within range and fires automatically. Towers unlock as your Player Level increases.
| Tower | Cost | Range | Damage | Fire Rate | Special | Unlock |
|---|---|---|---|---|---|---|
| iptables | 20 CPU | 150 | 15 | Medium | Balanced | Lv 1 |
| fail2ban | 30 CPU | 120 | 8 | Very Fast | Suppressive fire | Lv 3 |
| Snort IDS | 40 CPU | 220 | 25 | Slow | Long-range sniper | Lv 5 |
| ClamAV | 50 CPU | 130 | 10 | Medium | Slows enemies 60% | Lv 8 |
| SELinux | 60 CPU | 140 | 40 | Slow | Heavy hitter | Lv 12 |
| Firewall+ | 70 CPU | 100 | 5 | Slow | Heals server 2 HP/sec | Lv 16 |
| Honeypot | 40 CPU | 90 | — | — | Attracts & destroys (single use) | Lv 20 |
| CrowdSec | 80 CPU | 160 | 30 | Medium | Chain lightning hits 3 nearby | Lv 25 |
| AppArmor | 90 CPU | 110 | 20 | Medium | Reflects 30% damage in aura | Lv 30 |
| KernelGuard | 150 CPU | 200 | 80 | Slow | Ultimate defense | Lv 40 |
Click on a placed tower to select it. The side panel will show the tower's details along with UPGRADE and SELL buttons. You can also right-click a tower to sell it instantly.
When certain tower types are placed within 2 cells of each other, they activate powerful synergy bonuses. Active synergies are displayed in the side panel and shown on affected towers with a pink glow.
| Tower Combo | Synergy Name | Bonus |
|---|---|---|
| iptables + fail2ban | Layer 7 Defense | +15% fire rate |
| ClamAV + CrowdSec | Threat Intelligence | Chain also slows enemies |
| Snort IDS + SELinux | Deep Inspection | +20% damage |
| Firewall+ + AppArmor | Zero Trust | +2 HP/sec heal |
| Honeypot + CrowdSec | Honey Net | +40 honeypot range |
| iptables + Snort IDS | IDS Pipeline | +20 range both |
| SELinux + KernelGuard | Kernel Hardening | +30% damage |
| fail2ban + ClamAV | Rapid Quarantine | +20% slow effect |
Enemies spawn from the edges and move toward your server. Different types have unique behaviors that require different strategies. Beware of disguised enemies (Trojans and Phishers) — they appear green like friendlies until they get close!
| Enemy | HP | Speed | DMG | Special Behavior |
|---|---|---|---|---|
| Script Kiddie | Low | Medium | 5 | Basic threat |
| DDoS Bot | High | Slow | 8 | Tanky — absorbs damage |
| Malware | Medium | Fast | 7 | Fast and dangerous |
| Ransomware | Medium | Medium | 15 | Heavy damage on contact |
| Trojan | Low | V. Fast | 6 | Disguised as friendly until near |
| Rootkit | Medium | Slow | 10 | Heals nearby enemies every second |
| Botnet | V. Low | Fast | 3 | Swarm — appears in large numbers |
| Worm | Medium | Medium | 8 | Splits into 2 smaller enemies on death |
| Zero-Day | Medium | V. Fast | 20 | Extremely fast and lethal |
| Cryptojacker | Medium | Medium | 5 | Drains your CPU passively while alive |
| Phisher | Low | Fast | 12 | Disguised as friendly until revealed |
| APT (Boss) | V. High | Slow | 25 | Boss — huge HP, massive damage |
| Ability | Key | Cost | Cooldown | Unlock | Effect |
|---|---|---|---|---|---|
| sudo kill | Click | Free | None | Lv 1 | Click enemies to deal damage (scales with Player Level) |
| System Reboot | R | 30 CPU | 10s | Lv 5 | Restore 30 server HP |
| Kill All | SPACE | 80 CPU | 30s | Lv 10 | Destroy all enemies on screen |
| Overclock | O | 50 CPU | 20s | Lv 15 | Double all tower fire rate for 10 seconds |
| Backup Restore | B | 100 CPU | 40s | Lv 25 | Fully restore server HP to maximum |
Use the 1x / 2x / 3x speed buttons in the top-right of the HUD to accelerate gameplay. Speed affects enemy movement, tower firing, ability cooldowns, and passive CPU generation — but not the rendering quality. Press M or click the speaker icon to mute/unmute sound effects.
As you progress through levels, different maps introduce wall obstacles that block tower placement and force enemies to navigate around them. Walls create strategic choke points where towers are more effective. There are 6 map layouts that rotate based on the level tier, from open fields to complex spiral patterns.
The side panel shows a preview of the next wave's enemy composition, displayed as colored dots. Each color represents a different enemy type. A diamond shape indicates a boss. Use this information to prepare your defenses before the wave starts!
Killing enemies in quick succession (within 3 seconds of each other) builds a combo counter. The combo counter appears in the HUD and multiplies your score. Reach high combos for bonus points and achievements!
Every day, a new challenge is generated with fixed parameters (same for all players). Click the DAILY button in the controls panel to start it. Your best score is submitted to the daily leaderboard. Complete daily challenges for achievements and bonus XP!
After reaching game level 100 or player level 50, the ENDLESS button becomes available. Endless mode features infinite waves with ever-escalating difficulty. Your best wave is tracked on your profile and the leaderboard. How long can you survive?
The game tracks 25 achievements across combat, tower building, progression, and special challenges. Achievements award XP bonuses and are displayed on your profile page. Some achievements are hidden until you discover them. Examples include:
Killing enemies earns XP. Accumulate enough XP to level up your Player Level (max 100). Each level automatically improves your stats through upgrades:
| Upgrade | Scaling |
|---|---|
| Click Damage | +2 every 2 levels |
| Tower Damage Bonus | +5 every 5 levels (applies to all towers) |
| Tower Range Bonus | +5 every 4 levels (applies to all towers) |
| CPU per Kill | +1 every 3 levels |
| Passive CPU/sec | +1 every 10 levels |
| Server HP Bonus | +5 every 2 levels |
| Starting CPU Bonus | +5 every 3 levels |
| Critical Hit Chance | +1% every 5 levels (max 30%) |
Your attacks have a chance to deal double damage. Critical hits are shown in yellow floating text. The crit chance increases with your Player Level, up to 30%.
The leaderboard ranks all players by four metrics: Total Score, Highest Wave, Game Level, and Player Level. Visit your profile page to see detailed statistics, achievement progress, and play history. Your progress is saved automatically every 30 seconds and whenever you complete or fail a level.