Grandia: Parallel Trippers is a traditional role-playing video game that is presented using two-dimensional graphics and character sprites and is presented using an overhead perspective. Players must guide the main character Yuuhi through a number of environments containing non-player characters, enemy monsters, traps, and puzzles that must be overcome in order to advance. Obstacles such as ledges and pits may be overcome by jumping, and other hindrances such as barricades and walls may be crossed using switches found in the area. The accompanying character Pinky, a rotund, flying creature with large ears, can also be used to manipulate objects from a distance. Treasure chests containing beneficial items such as healing herbs and equipment are scattered throughout each area, in addition to hidden items that must be found by searching certain objects. Like the original Grandia, enemies in Parallel Trippers are visible on the map screen, and are only engaged when a player comes in contact with one.

Combat in Parallel Trippers has been modified from the original game, yet still retains the Initiative Point Gauge ("IP Gauge") for determining the order of actions. Neither characters in the player's party nor enemy monsters move about the combat field, and are instead restricted to fixed positions observed from a first-person perspective. As a party member or enemy's turn approaches, a representative icon on the bottom of the screen moves along the IP Gauge to its end, the speed of which being determined by the particular character's "speed" rating. Once a character's icon has reached the end of the gauge, it becomes their turn to act, with all other activity halting until the player has selected their action. Players may choose to attack an enemy or use a magic-based attack by selecting an appropriate "Synthesis Card" from their inventory. Synthesis Cards may also be used in combination with each other to produce additional effects or unlock special magic attacks. As a player's party defeats enemies, they earn experience points that go toward gaining levels, making each character stronger. Throughout battles, players also collect data on enemy monsters, actions, and characters that are stored in the game's database accessible from the title screen.