Sublevel Zero

Sublevel Zero is a first-person shooter with a retro look played controlling a gunship with the six degrees of freedom principle for movement, inspired by games like Descent and Forsaken. The game is set in a universe where reality is falling apart and the player is a lone gunship pilot. Wormholes and strange events have scattered humankind and most technology has been lost. The remaining people form clans and are preyed upon by warlords who still possess ships. The pilot discovers an ancient facility in an uncharted system. The gunship descends into the facility to recover technology needed for the pilot's clan to survive and possibly reverse the events that are causing the universe to fall apart.

The game consists of six levels that are procedurally generated for level design, enemies and item placement. Each level contains a reactor that needs to be destroyed to acquire parts of a flux drive. Next to the randomized design there are many other roguelike elements such as permadeath and a selection of random power-ups as permanent perks after completing a level. The game is completed when the flux drive is completely reassembled. In the zero gravity environment the ship can move in any direction, combined with rolling. It is also possible to boost for a short time with a recovery period. The ship has an inventory for parts and six slots: two for regular guns, two for launchers, one for the engine and one for the hull. Defeated enemies often leave behind parts that can be picked up to replace the equipped ones or to store them in the inventory. Both primary and secondary weapons come with three types of ammo, so it is often needed to switch between the weapons as ammo is scarce. Weapons have different statistics for firing rate, damage and acceleration. There are shotgun-like weapons with small parts, instagib weapons like a railgun, rifle-like weapons firing a constant stream etc. The secondary launcher weapon are much more powerful with rockets and homing missiles, but in small quantities. The ship has a limited amount of health. Health kits can be picked up and stored to replenish health as death is permanent. Room in the inventory is limited, so often parts need to be dropped as well.

Nanites are the main currency found in chests or by defeating enemies. They are used for crafting and to earn nanocarts. Many weapon parts can be combined into exotic variations using nanites as a currency, for instance creating a shotgun-like weapon combined with a flamethrower. Some enemies also leave behind log data files that can be read. After completing a level, a perk from a random selection can be chosen if enough nanites were collected to earn a nanocart. Examples are a self shield, more accuracy while lowering the fire rate, more return from pick-ups etc. Most of these perks offer an advantage while also taking something away. The game also has a class system where up to seven different gunships can be selected before starting a new game: berserker, hulk, hunter, larva, pyro, standard or stormtrooper. They are unlocked gradually and only the standard one is available right away.