Planetariums are special rooms added in containing astronomical items.
The Binding of Isaac: Repentance
+2 red Heart containers, -0.3 speed. Isaac builds speed while standing still, and releases poison gas clouds when he moves with increased speed.
Adds an extra Secret Room and Super Secret Room to each floor. Secret Rooms contain a beam of light that increases tears for the current floor and give soul hearts.
Dash by double-tapping the movement key, becoming invulnerable and damaging enemies. There's a short cooldown before Isaac can dash again.
+0.4 speed. Doors stay open after entering a room, even in rooms with enemies.
While not firing, Isaac builds a massive tears bonus over 3 seconds. The tear bonus falls off rapidly as Isaac fires.
Significantly shrinks Isaac, allowing him to squeeze between objects and makes some enemy shots pass over him. Also gives +0.7 tears.
Upon entering a room, a circle of tears orbits Isaac. Enemy tears have a chance to be caught in orbit, turning them friendly.
Reveals the location of the Boss room. Upon defeating a boss, activates XIX - The Sun, fully recharges Isaac's active item, and grants bonus damage and luck for the rest of the floor.
Replaces tears with rocks that deal variable damage, have increased knockback, and can destroy obstacles.
Isaac shoots ice tears, which slow enemies and freeze monsters they kill. Frozen enemies slide away and explode into ice shards when touched.
Adds one red Heart container. Enemies near Isaac become charmed.