“Reasonable Claustrophobia” by Retrosaur & Clockwise2000.
“The [aliens] […] have built themselves a claustrophobic base! Kill them and their leader before they keep building these counter-intuitive monoliths!”
“Reasonable Claustrophobia” is not only a puzzle shooter with some amazing old-school graphics, which is basically all about eliminating all opponents in a level and thereby activating the level exit. Instead, a special twist was added to this core concept gameplay-wise: Whenever you or your opponent shoot at the walls, the walls will move closer to you. This can be a disadvantage, because in the worst case the exit gets blocked. However, you can also use it to let the walls rush against your opponents from behind, so that they will simply fall off their platform. >>PLAY