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Watch trailer on Steam ↗Space Mercenary Defense Force
Tom Paradise · Published by Tom Paradise
Positive — 89% positive (18 reviews) · 56 achievements
Last updated 27 Sept 2026
Defend against the alien invasion and take down the mother ship! Utilise branching upgrade trees, unlock new ships, and equip permanent upgrades to create your own unique build and defeat the growing hordes of invaders in this sci-fi action roguelike!
£4.29
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Price history
Action, Indie, RPG, Casual · 2023 · More under £5 games
Take on the alien invasion in Space Mercenary Defense Force, where your choices shape a unique defense strategy. Utilize diverse upgrades to outmaneuver and destroy the enemy fleet.
About this game
Combine Different Ship Modules Each Run
Equip your ship's directional module slots with various module types such as explosive, defensive, deployable, beam, & more!Choose Your Own Upgrade Paths
Featuring over 600 upgrades with unique progression via branching paths you can make each run different and unique with your choices.Optional Encounters
Complete optional random Encounters like fighting minibosses or charging a conduit to earn rewards and further level up your ship!Dynamic Threat Events
Aliens aren't your only threat! Survive the various timed threats such as Off-World Targeting, Outer Atmosphere Lightning, Pulsing Solar Flares, & more!Permanent Upgrades And Unlocks
Spend your hard earned credits on new ships, skins, & permanent Astral Upgrades and complete objectives to unlock ship perks, and Celestial Modifiers!System Requirements
Will my PC run this? →Minimum
- Requires a 64-bit processor and operating system
- OS: Windows 10 64bit
- Processor: Dual Core+
- Memory: 2 GB RAM
- Graphics: 2GB VRAM
- Storage: 500 MB available space
Recommended
- Requires a 64-bit processor and operating system
Supported Languages
Latest news
Patch NotesOfficial
v1.0.2.3 - Bug Fixes
Fixed issue with encounter reward upgrade choices where the sprite and colour was incorrect for synergy and final upgrades. Fixed Outer Atmospheric Lightning animation not playing correctly after pausing or levelling up while the threat event is active. Fixed the charger miniboss counting as 2 completions for the encounter when killed. Fixed Armour Repair Drones now correctly gives 1HP on pickup. Fixed the turbo mode text now changing to the high res font when selected. Fixed game over stats and credits text scaling issue when the high res font is selected. Fixed text panel scaling issue for ship skin descriptions when high res font is selected. Fixed controller navigation issue with the unlock popup screen when scrolling to the final unlock. Fixed controller navigation issue when closing the ship skin select so now the skin button is selected instead of the perk button. Fixed ship skin hover descriptions staying active after closing and reopening the skin select menu.Read full article on Community Announcements (SirMrTom)Patch NotesOfficial
v1.0.2.2 - Bug Fixes
In the game over screen, changed the displayed equipped perk icon so that nothing is shown for locked or unequipped perks. In the game over screen, changed the layering so that the equipped perk icon is behind equipped module names. Fixed an issue displaying HP that affected ships with more than 3 HP. Fixed issue with minibosses and the laser teleporter miniboss' portal remaining when returning to the menu. Fixed the ship purchase sfx stopping early. Fixed the clone backup challenge modifier so that the clone bosses no longer affect boss HP bar values. Made it so that the laser twin bosses cannot be ionised while performing their double spin laser attack. Fixed Area Select Module from flying offscreen after the target enemy dies. Fixes to the interactions of bosses spawning while the previous boss is still alive: If more than 1 boss is alive at once, the screen now only unlocks after all are killed. Previous bosses will not affect the displayed HP bar of the most recently spawned boss. After killing a boss, the HP bar will change to match the other boss. Fixed the game not ending and softlocking after killing the final boss if the final boss spawns before you can kill the previous boss/bosses. Fixed controller UI navigation issues: Coin toss: fixed not being able to select the double or nothing button. Coin toss: fixed losing controller navigation after unpausing while the coin toss screen is open Astral Upgrades: fixed not highlighting the default selected button upon opening the Astral Upgrade screen.Read full article on Community Announcements (SirMrTom)AnnouncementsOfficial
v1.0.2.1 - Unique Boss HP Bars & Fixes
Boss HP Bars Added full-sized HP bars for boss fights with unique icons for each boss. Including double HP bars for the laser twin boss fight. {STEAM_CLAN_IMAGE}/43273427/f51689eb26c259659ea02ed41b58f87d145abcd6.png Fixes Fixed score and streak not displaying in the game over screen if score tracking is disabled in the options. Fixed Astral Upgrades not showing their new values upon buying stacking upgrades (until restarting).Read full article on Community Announcements (SirMrTom)AnnouncementsOfficial
v1.0.2 - Boss Death Animations, Camera Transitions, & HP Bars
Boss Changes This update focuses on quality of life and clarity improvements regarding bosses and boss deaths. Bosses now have a visible small HP bar similar to module charge bars on them so you know your progress in defeating them and how close they are to death. Also added are death animations for all bosses similar to the player death animation where explosions trigger and the boss splits into pieces before fading out. Lastly, after the animation has ended, the camera will no longer instantly jump back to centering the player. Instead, it now pans over to it's new position over a 1 second duration, creating a smoother, less jarring transition to returning to the non-boss gameplay. Fixes Fixed issue where the laser bosses would continue looping their laser beam SFX after the first is killed while it is playing.Read full article on Community Announcements (SirMrTom)Patch NotesOfficial
Controller UI Hotfixes - v1.0.1
Fixed an issue when trying to select the 4th or 5th challenge invasion in a system with a controller. When returning from the challenge invasion screen with a controller, the challenge invasion button will now be selected. When entering the mode select screen with a controller, the classic mode button will now be the default selected button instead of the challenge invasion button.Read full article on Community Announcements (SirMrTom)






