One-man Spanish indie powerhouse Locomalito (and much credit to his musical compatriot, Gryzor87) has come up trumps once more. Today marks the release of his fourth game, Viriax. Like his previous three titles, it is two things above all else: Brilliant and free.

Billed as ‘Arcade medical terror’, you control an adorable, murderous little 8-bit viral creature, on a mission to not only demolish every single major organ inside the human you reside in, but (presumably as a final act of microscopic spite) also destroy the implanted nanomachine factory that has been generating all the obstacles between you and the delicious, juicy core cells of each organ.

Over the course of the game, you’ll traverse six regions of the body, each consisting of 80 vertically stacked and randomly generated ‘floors’ worth of action (every 20th containing a boss). It’s an incredibly simple and accessible game, played entirely using the arrow keys. Up makes you jump, and repeated taps make you ‘swim’ upwards. The left and right keys maneuver you, and the down arrow causes you to pounce on whatever lies directly below you, dealing damage, and cracking open glowing cells in order to reap bonus points or temporary powerups.

Simple, but not easy. Every action beyond moving left and right or the initial jump from a solid platform will drain your energy bar. Every attack, every stroke of swimming will take a chunk out of it, and more often than not, you’ll have to attack or swim to progress. So along the way, you need to collect a steady stream of red blood-cells to restore your health. Some dropped by enemies, others occurring naturally, they’re always in short supply. You really need to pick and choose your fights. Do you leave an enemy alone and keep swimming, or risk attacking them in the hope that they contain more health? It’s very easy to back yourself into a corner and doom your little red virus-monster to an early disintegration.

It’s intense and very stressful. You’ve got no time-pressure working against you, but every action you take beyond the very most basic is a drain on your limited resources, and it forces you to really think hard and fast, as the quick-and-easy route of just swimming upwards at full speed is one of the fastest ways to die. I could spend a lot longer gushing about just how tightly designed this is, just how cleverly the powerups trick you into pushing too hard and making mistakes, and how scoring high requires a vastly different playstyle compared to mere survival, but I won’t. It’d be fairly redundant, considering that the game is free, under 3mb, and available to download now.

Grab it, and get down with the sickness.

Full Disclosure: Locomalito was kind enough to send me several early test builds of this game, and I offered a little help with tightening up translations and balance.