Like Psyvariar: Complete Edition, Psyvariar Delta combines both of the original versions of Psyvariar with new content. All versions of the game features Psyvariar 's trademark systems: buzzing and rolling. Buzzing rewards the player for grazing the edge of bullets, encouraging risky styles of play. Buzzing grants the player points as well as experience points, which lets the player's ship rank up; ranking up boosts the ship's power and also grants access to some of the game's later levels. When the player's ship ranks up, it also gets a special effect, such as temporary invincibility. Buzz combos build up over the course of a level, but reset to 0 when the player is hit by a bullet. Rolling allows the player to perform a barrel roll by tapping the joystick rapidly back and forth; while rolling, the player's ship moves at a different speed from usual and the shot is focused into a tighter pattern. Unlike the original arcade version, rolling can also be performed by holding down the roll button. Also unique to Psyvariar is a branching level system. After each level, players are given one of several alternate options to choose from, leading to many possible routes through the game. Higher-difficulty levels are only accessible if the player has reached a particular rank, so the game becomes longer as the player becomes more skilled.
The main game mode allows players to mix and match elements from Psyvariar: Medium Unit and Psyvariar: Revision. In addition to selecting between the original soundtracks or the brand-new Psyvariar Delta soundtrack, players can select one of several ships and game modes. The ships are:
In addition to the traditional arcade mode, a practice mode lets the player try any stage with a specified number of lives, bombs, and experience. A replay mode also lets the player watch replays of their previous games.