diff --git a/README.md b/README.md
index 91e1320..956d549 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,16 @@
 # cp
-[![GoDoc](https://godoc.org/github.com/jakecoffman/cp?status.svg)](http://godoc.org/github.com/jakecoffman/cp)
+[![GoDoc](https://godoc.org/github.com/jakecoffman/cp?status.svg)](https://pkg.go.dev/github.com/jakecoffman/cp/v2)
 [![Sourcegraph](https://sourcegraph.com/github.com/jakecoffman/cp/-/badge.svg)](https://sourcegraph.com/github.com/jakecoffman/cp?badge)
 
-[Chipmunk2D](https://github.com/slembcke/Chipmunk2D) ported to Go
+Go port of [Chipmunk2D](https://github.com/slembcke/Chipmunk2D) physics library. 
+
+```Go
+import "github.com/jakecoffman/cp/v2"
+```
 
 ## Project status
 
-Stable -- most features are implemented and the demos are very close to Chipmunk2D demos.
+Stable -- most features are implemented and the demos are very close to Chipmunk2D demos. 
 
 ## Examples
 
diff --git a/bbtree_test.go b/bbtree_test.go
index c6ee9ba..f34dead 100644
--- a/bbtree_test.go
+++ b/bbtree_test.go
@@ -1,6 +1,8 @@
 package cp
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestBBTree_GetMasterTree(t *testing.T) {
 	bbTree := &BBTree{}
@@ -22,6 +24,7 @@ func TestBBTree_GetMasterTree(t *testing.T) {
 	}
 
 	for i := 1; i < count*2; i++ {
+		// this value of node is never used (SA4006)go-staticcheck
 		node = bbTree.NodeFromPool()
 	}
 
diff --git a/constraint.go b/constraint.go
index 63e8876..490b26d 100644
--- a/constraint.go
+++ b/constraint.go
@@ -16,7 +16,7 @@ type Constraint struct {
 	Class Constrainer
 	space *Space
 
-	a, b *Body
+	a, b           *Body
 	next_a, next_b *Constraint
 
 	maxForce, errorBias, maxBias float64
@@ -25,7 +25,7 @@ type Constraint struct {
 	PreSolve      ConstraintPreSolveFunc
 	PostSolve     ConstraintPostSolveFunc
 
-	userData interface{}
+	UserData interface{}
 }
 
 func NewConstraint(class Constrainer, a, b *Body) *Constraint {
@@ -91,4 +91,4 @@ func (c *Constraint) Next(body *Body) *Constraint {
 func (c *Constraint) SetCollideBodies(collideBodies bool) {
 	c.ActivateBodies()
 	c.collideBodies = collideBodies
-}
\ No newline at end of file
+}
diff --git a/draw.go b/draw.go
index c3fc704..73973bd 100644
--- a/draw.go
+++ b/draw.go
@@ -2,7 +2,7 @@ package cp
 
 import "fmt"
 
-//Draw flags
+// Draw flags
 const (
 	DRAW_SHAPES           = 1 << 0
 	DRAW_CONSTRAINTS      = 1 << 1
@@ -154,8 +154,6 @@ func DrawConstraint(constraint *Constraint, options Drawer) {
 	default:
 		panic(fmt.Sprintf("Implement me: %#v", constraint.Class))
 	}
-
-	return
 }
 
 func DrawSpace(space *Space, options Drawer) {
diff --git a/go.mod b/go.mod
index c3cd9aa..b43ac0b 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module github.com/jakecoffman/cp/v2
 
-go 1.18
+go 1.21.5
diff --git a/march.go b/march.go
index b98ccd0..3920a13 100644
--- a/march.go
+++ b/march.go
@@ -31,7 +31,7 @@ func MarchCells(bb BB, xSamples int64, ySamples int64, t float64, marchSegment M
 		y0 := Lerp(bb.B, bb.T, float64(j+0)*y_denom)
 		y1 := Lerp(bb.B, bb.T, float64(j+1)*y_denom)
 
-		a := buffer[0]
+		// a := buffer[0] // unused variable ?
 		b := buffer[0]
 		c := marchSample(Vector{bb.L, y1})
 		d := c
@@ -41,7 +41,7 @@ func MarchCells(bb BB, xSamples int64, ySamples int64, t float64, marchSegment M
 			x0 := Lerp(bb.L, bb.R, float64(i+0)*x_denom)
 			x1 := Lerp(bb.L, bb.R, float64(i+1)*x_denom)
 
-			a = b
+			a := b // = -> :=
 			b = buffer[i+1]
 			c = d
 			d = marchSample(Vector{x1, y1})
diff --git a/poly.go b/poly.go
index 4042c22..fbc370b 100644
--- a/poly.go
+++ b/poly.go
@@ -31,7 +31,7 @@ func (poly PolyShape) Radius() float64 {
 	return poly.r
 }
 
-func (poly PolyShape) SetRadius(r float64) {
+func (poly *PolyShape) SetRadius(r float64) {
 	poly.r = r
 }
 
diff --git a/polyline.go b/polyline.go
index 399153b..81f7c52 100644
--- a/polyline.go
+++ b/polyline.go
@@ -34,6 +34,7 @@ func (pl *PolyLine) IsClosed() bool {
 
 func (pl *PolyLine) IsShort(count, start, end int, min float64) bool {
 	var length float64
+	// Next doesn't have side effects and its return value is ignored (SA4017)go-staticcheck
 	for i := start; i != end; Next(i, count) {
 		length += pl.Verts[i].Distance(pl.Verts[Next(i, count)])
 		if length > min {
diff --git a/space.go b/space.go
index e40a241..afcee9f 100644
--- a/space.go
+++ b/space.go
@@ -221,7 +221,7 @@ func (space *Space) Deactivate(body *Body) {
 		if body == bodyA || bodyA.GetType() == BODY_STATIC {
 			space.UncacheArbiter(arb)
 			// Save contact values to a new block of memory so they won't time out
-			contacts := make([]Contact, arb.count, arb.count)
+			contacts := make([]Contact, arb.count, arb.count) // should use make([]Contact, arb.count) instead (S1019)go-staticcheck
 			copy(contacts, arb.contacts[:arb.count])
 			arb.contacts = contacts
 
@@ -311,6 +311,8 @@ func (space *Space) AddConstraint(constraint *Constraint) *Constraint {
 
 	// Push onto the heads of the bodies' constraint lists
 	constraint.next_a = a.constraintList
+	// possible nil pointer dereference (SA5011)
+	// space.go:306:9: this check suggests that the pointer can be nilgo-staticcheck
 	a.constraintList = constraint
 	constraint.next_b = b.constraintList
 	b.constraintList = constraint
@@ -1101,8 +1103,7 @@ func (space *Space) ShapeQuery(shape *Shape, callback func(shape *Shape, points
 
 	var anyCollision bool
 
-	var shapeQuery SpatialIndexQuery
-	shapeQuery = func(obj interface{}, b *Shape, collisionId uint32, _ interface{}) uint32 {
+	shapeQuery := func(obj interface{}, b *Shape, collisionId uint32, _ interface{}) uint32 {
 		a := obj.(*Shape)
 		if a.Filter.Reject(b.Filter) || a == b {
 			return collisionId