Vlambeer , the developer of Nuclear Throne and Luftrausers, celebrated its eighth birthday with quite the surprise at PAX West 2018 — a brand new, never-before-seen game.

Vlambeer's Untitled Space Shooter 23 IMAGES

Unexpectedly playable at the Vlambeer booth at PAX, the game is currently untitled, and involves a one-button setup. Moving with the arrow keys, the player controls a ship around a contained field, shooting with the X key.On the surface, Vlambeer's next game — which has no planned release date or launch platforms — looks like a standard bullet hell shoot'em up. But there's a deceptively deep strategy to the demo we played at PAX. The player can't aim their ship while shooting — the ship instead aims itself as you move it while not blasting, locking onto the nearest enemy.To further complicate it, new enemies don't just continuously spawn. Shooting the first enemy spawns some green space goo that, when the player's ship moves far away enough from it, produces new enemies. Some of them behave differently, shooting out different types of projectiles, and as you can see in the images above, the screen can become jampacked with enemies, some who like to chase the player ship around and deadly energy beams.The game in its current state offered high scores to chase and hinted at an unlock system for new power-ups and ships based on different enemy types, but given that there's currently no release cycle planned for it, plenty could change.Vlambeer's Rami Ismail told us they weren't even planning to show the game at all, and spontaneously did so to celebrate the company's birthday. Ismail also said that the studio was interested in getting back to their roots and making small games like this after working on Nuclear Throne for so long.You can see gameplay of Vlambeer's new game in the interview video at the top of the page, and stay tuned on IGN for more from PAX West 2018.

Jonathon Dornbush is IGN's News Editor from IGN. Find him on Twitter @jmdornbush