Top similar games like Fortitude invasion:

Magic Time is an adventure in the arcade genre with a magical setting.

Sisyphus Paradox is a fusion of roguelike tactical elements with classic side-scrolling shoot 'em up gameplay. Explore and fight your way across the galaxy as you try to get back home to Earth in this hand drawn indie game.

Mini Island: Winter is a one small hold & Gun, boss Rush mini-game of Casual difficulty!

Mixx Island: Remix Vol. 2 is a one small hold & Gun, boss Rush mini-game of Casual difficulty! This beautiful place was built only for simple fun! Choose the character and difficulty level that best suits you and enjoy a short, simple but colorful boss rush minigame!

Helvetii is a character-action game set in Gallic Celtic Mythology. Challenge the everchanging rot with 3 characters, use the gifts and powers bestowed by primal deities and show your mastery of combat by pummeling, juggling and slamming your enemies in a gorgeous 2d presentation.

Cell Wars is a classic arcade shooter where your goal is to consume all enemy cells by shooting and eating them. Inspired by NES graphics, gameplay from arcade 80s cabinets, and early 2000s skill tree systems. Unlock abilities and skills to survive waves of regular, elite and boss cells.

AlphaLink pits players in a dystopian intergalactic arena multiplayer battle to shift the tides in the war of factions!

A coalition of large corporations trying to destroy the root flowers is invading Daejeon. Protect the root flowers. It's not going to be easy. Because... Roots Need Control.

You are a special purpose soldier and your goal is to destroy some settlement, which is inhabited by a bunch of sorcerers.

Explosive, balls-to-the-wall bullet hell shooter with novel shooting mechanics (and surreal comedy)

Show Lil' Beezey who the boss of Winkletown is in this addictive and fast paced 2D action roguelite! Created from scratch in only 14 days and nominated for GDWC Game Jam GOTY, Soulvester comes to Steam for the first time, now with controller support and achievements!

Dodge, shoot, survive! Polygon pursuit is an arcade-style twin stick shooter where you are pursued by multiple enemies constantly. You play as a lone circle confined in a polygonal world fighting to survive against waves of unique enemies. This is not an easy game.

A satisfying shooting game with 4 gameplay modes and simple controls! Upgrade your character and defend the Portal from the creatures of the void.

Slayer Cat is a classic action shooter game that combines hand-drawn drawings with classic gameplay. Inspired by games like Contra, Doom, and Cuphead. Play as The Slayer Cat as you traverse strange places on an enemy planet, and discover and discover the mysteries of this place!

ASTRO: The Beginning is a dynamic side scrolling shoot 'em up about a close-knit space team caught in a clusterf*ck of epic proportions.Unravel the evil plans of your foes and secrets of world order while taking down various types of enemies and engaging in crazy boss battles.

Atomorf loves radiation and collects plutonium, but is afraid of very hot and sharp objects.

Survivors of the Mare Vitalis is a Rogue-Lite action game, which you can discover unique planets and it's biomes while thousands of animals and uncategorized life forms coming after to kill you!! Earn Credits while destroy them, upgrade yourself and destroy the Ecosystem of each planet!!

Goblin Survivors - casual goblin destruction simulator with roguelike elements. Pump up destructive magic, erase hundreds of vile monsters, survive in battles with bosses! Make up your set of spells before foray into the lands of the enemy, for the most effective extermination!

Not just a platformer, but a mega cool and colorful game about a cube, a character with tons of abilities in a fun kingdom of geometric figures called ShapeSpring. The graphics are lit! The controls are lit! And the animations are mmm, I don't know what else you're waiting for, let's play!

The Final Frontier is a retro multi-directional shooter inspired by the likes of Asteroids and Galaga. You destroy waves of endless enemies while trying to survive as long as possible by upgrading your ship's abilities along the way.

Blast your way through a myriad of extra-terrestrial incursions in this arcade-style scrolling shooter! Pilot the ship Habroxia through 15 levels featuring intense boss fights, rescue missions, shifting perspectives, and untold surprises.

99 Levels to Hell is a platform shooter with lots of guns, upgrades, magic, traps and monsters to kill. 99 Levels to Hell is a rogue-like, which means surviving is key and every time you play you get a new set of levels to play. When you complete 10 levels, the 10th being a boss-fight you unlock a door to the next dungeon.

A side scrolling shooter with a bullet hell influence. Does it explode? Yes. Everything does. Enemies show their battle damage through having chunks be blown off. There are multiple enemies all with unique behaviours, all which are designed in junction with each other.

Hit Confirmed is an arcade survival game and scoring.

FULL-THROTTLE STG "ACCELERATE ZONE". This is an action shooting game where the faster you go, the better your strategy. It's okay to take your time and go at your own pace.

1917 - The Alien Invasions is a bullet hell memorization shooter. Dr. Brunhild Stahlmüller upgrades an WW1 Triplane with superior alien technology to attack the invaders. She will avenge mankind and take the battle into the darkness of space until she reach an ancient alien world.

You play as a ninja fending off waves of various types of ghosts, each getting increasingly difficult from the last. How many waves can you last before the ghost onslaught overwhelms you.

You have to solve puzzles and switch gravity.

Duel of Honor is a dynamic battle on flying motorcycles, a gloomy atmosphere, bright music and memorable gameplay. The victory will be yours!