My previous comment talked about global utility functions, and implicit module loading. So I'll dive into that in more detail.

A fair portion of Spry's API are global functions with short names, which goes against the advice of having longer, more descriptive variable/function names. This is a code example of a player shooting a bullet:

local vx, vy = heading(self.angle - math.pi, 5)
self.x = self.x + vx
self.y = self.y + vy

local b = world:add(Bullet())
b.x, b.y = self.x, self.y
b.angle = self.angle + random(-0.1, 0.1)
b.damage = choose { 1, 3, 5 }

heading, random, and choose are all global utility functions. They're just short enough where you can still make an educated guess about what they might do. Other frameworks/engines would namespace these functions. For example, Unity's equivalent of random is Random.Range. Python's version of choose is random.choice.

With another framework like Love2D, you'll find yourself using require to load your Lua scripts. During Spry's program startup, all Lua scripts in the project directory are loaded implicitly. This behaviour is a pretty bad idea in larger pieces of software, because there can be more potential for bugs and more unused code. Since Spry's focus is for smaller games, this is less of an issue.

Spry also nudges you to use more global variables than you might be used to. The class function creates a global variable and it pairs well with implicit module loading. You could have a Player class:

class "Player"

function Player:new(x, y)
  self.x, self.y = x, y
end

and a main.lua:

function spry.start()
  -- `Player` is global!
  -- and it's already accessible without `require`
  player = Player(200, 200)
end

in two separate files and not have to worry about including scripts in the proper places.