The Genius of Prey's Gloo Cannon

ALARM CLOCK: Good Morning Morgan. Today is Monday March 15th, 2032 Prey is packed with good ideas. Like, the Mimic. This spindly, black, spider-like alien can disguise itself as any object in the room - making you suspicious of everything you see. See that health-pack? Surprise! It’s a Mimic. But, you can also take that power for yourself. You can use these painful looking Neuromods to give yourself alien powers - one of which lets you turn yourself into a coffee mug, roll through a gap in a door, and then turn back into a human on the other side. Handy.

However, collecting these powers comes at a cost. Install too many and the friendly robots aboard Talos I will read your DNA as alien, and start targeting you as an enemy. Like I said, Prey is stuffed with smart ideas. But perhaps the best of all is found right at very the start of the game: the Gelifoam Lattice Organism Obstructor - or, as it’s better known, the Gloo cannon. It’s the game’s signature weapon and like Kratos’ Leviathan Axe or Mario’s cap, this thing serves so many purposes that you’ll always want to have it on quick-select.

So, as soon as you snatch it, you’re invaded by an army of Mimics. And when you hit them with the Gloo cannon’s big blobs of insta-dry adhesive, you’ll immediately figure out its first major use: freezing enemies in place. Kinda like the electric bolt in Bioshock or the ice missiles in Metroid, the Gloo cannon temporarily stops enemies in their tracks and lowers their defence, giving you a chance to swap to another weapon for a decisive blow.

Or, scan them with your psychoscope to boost your research. Or just run away. Another use for the Gloo cannon is to deal with environmental hazards. You can use it to plug up gas leaks and stop flames spewing out. Or patch up a malfunctioning electrical circuit, to give you time to fix it. Or use a blob of Gloo to sponge up toxic spills left by nuisance enemies. Or exploit the physics system to move hefty objects that Morgan can’t lift by hand.

But it’s the third and final use of the Gloo cannon that takes this thing from a handy gadget to an essential piece of equipment: Gloo blobs stick to practically any surface, bar glass, and then stay there indefinitely - allowing you to clamber on top of them and reach high-up zones. So right next to you when you get the Gloo cannon there’s a half-finished staircase which leads you up to this roof, and nets you few goodies.

But then you might notice that this whole area is actually comprised of multiple floors and the grav shaft elevator is out of action. So, if you use the Gloo cannon to build a makeshift staircase you’ll be able to reach the next floor and grab some extra stuff - including early access to a new weapon. If you didn’t quite figure that out for yourself, later in the game you’ll watch a character create a Gloo staircase right in front of you to reach an escape route.

Staircases aren’t the only thing you can make, though: later in the game you can unlock a Neuromod called Lift, which creates a blast of antigravity and sends hefty objects high into the air. You can then Gloo them to walls, to create floating platforms. Theoretically you could then destroy the Gloo and have the object crash down on an enemy’s head, but I think that would be more luck than anything. I spent about 30 minutes trying to get this to work and this was the best I could manage.

So the Gloo cannon can be used to get up to all sorts of high places, allowing you to find secret stashes of items. It feels like a more intentional version of the classic Deus Ex trick of using LAM mines to climb up walls - and a natural expansion of the movement options in Arkane’s other immersive sim, Dishonored. That game had to limit the player’s movement with high-reaching walls, to keep them in one small part of a much larger world.

but a space station is very different. In an interview with PC Gamer, Prey’s lead system designer Seth Shain said “Because you're on the space station Talos I and outside of that is space, everything has a ceiling. With that, we knew that the bounds of the player were already set by the ceiling, [so] we could just let the player move through that space as fluidly as they could”. And, naturally, that means Gloo can also be used to let you skip past sections of the game or get to places earlier than you’re supposed to.

Take, for example, the Arboretum. When you first get there, you’ll find that Alex’s office is completely off limits, thanks to a locked down grav shaft. You won’t get the key code until much later in the game, and while you can bypass the lock you probably haven’t spent enough Neuromods on hacking by this point. However, when I got to this part of the game I used a whole bunch of Gloo (plus a fair amount of patience) to scramble up the inside of the elevator shaft and reach his office hours before I was supposed to.

And Arkane probably didn’t intend players to use the Gloo gun to clip through walls, completely break the game’s progression, and finish the whole adventure in less than 7 minutes time. Collision breaking aside, though, the Gloo gun is actually something of a technical marvel. Games are great at letting players remove stuff from a world - you know, enemies, objects, sometimes entire walls and chunks of planets - but adding new things is something entirely more difficult.

Having to draw too many objects can tank the game’s frame rate. Even my PC struggles to keep up with 2,000 cheese wheels in the same street. And saving all this additional stuff in memory isn’t always possible, which is why bullet holes disappear after you’ve created too many. And that’s not to mention that Prey’s Gloo blobs are physical objects that you can stand on - hence, the collision issue. Of course, adding objects is totally possible, but usually with restrictions.

Minecraft has simple voxel-based graphics and is constrained to a grid. Dreams has a creation budget that you can’t exceed. And Shadow Complex - which has a similar gadget to the Gloo cannon in its Foam gun - is saved by being in only two dimensions. So, to that end, the Gloo cannon also has some restraints. There is a limit to the number of blobs in one area, but unless you're cheating, your ammo will surely run out before you ever see it.

The most obvious limitation, though, is that while Gloo can stick to most things, it can’t stick to other blobs of Gloo. So you can’t make big towers or bridges. Shain says “that's something that we couldn't do because it created this technical problem - this chain of constraints that added to the computation time [of] the whole chain. There was no way we could do this and have it perform on console”. So while the Gloo gun went through lots of iterations and prototypes, lead designer Ricardo Bare told PCGamesN that “the version we ended up with was the best intersection of: performs well enough to ship and is the most fun”.

So, Prey is a game that is all is about choice. Male or female? Human or alien? Save or sacrifice? Which Neuromods do you pick? How do you explore the space station? Who do you trust? At every turn, the game gives you the power to choose your own way to play. And the Gloo cannon is a potent symbol of that player empowerment because it can serve you no matter how you choose to play - from combat to pacifism to exploration to problem solving to sequence breaking silliness.

It’s that multi-purpose design that makes the Gloo cannon one of gaming’s most ingenious gadgets. Thanks for watching! It’s always fun to go really deep on a single idea from a game. To that end, check out these similar videos on two more multipurpose game mechanics, the Leviathan Axe from God of War, and Cappy from Super Mario Odyssey. Cheers. See you soon.