diff --git a/component.go b/component.go
index 683ce2e..a22c4d9 100644
--- a/component.go
+++ b/component.go
@@ -43,7 +43,7 @@ func componentIDByName(name string) componentID {
 	if !w.haveSystemComponentName[name] {
 		w.systemComponentNames = append(w.systemComponentNames, name)
 		w.haveSystemComponentName[name] = true
-		id := newComponentID() // ComponentNames index now aligns with componentID
+		id := newComponentID()
 		return id
 	}
 
@@ -88,7 +88,13 @@ func (e Entity) With(f interface{}) {
 	args := make([]reflect.Value, numIn)
 	for i := 0; i < numIn; i++ {
 		id := componentIDByName(t.In(i).String())
-		args[i] = reflect.ValueOf(components[id])
+
+		arg := reflect.ValueOf(components[id])
+		if components[id] == nil {
+			arg = reflect.New(t.In(i)).Elem()
+		}
+
+		args[i] = arg
 	}
 
 	v.Call(args)
diff --git a/entity.go b/entity.go
index 2bd60c3..f8a4265 100644
--- a/entity.go
+++ b/entity.go
@@ -24,9 +24,6 @@ func NewEntity() Entity {
 	w.allEntities = append(w.allEntities, w.maxEntityID)
 	w.components = append(w.components, make([]interface{}, w.maxComponentID+1))
 
-	for i := range w.systems {
-		w.systemComponents[i] = append(w.systemComponents[i], make([]interface{}, w.maxComponentID+1))
-	}
 	return w.maxEntityID
 }
 
diff --git a/world.go b/world.go
index e957249..b60fcce 100644
--- a/world.go
+++ b/world.go
@@ -57,7 +57,6 @@ type world struct {
 	systemNeeds           [][]componentID   // Slice of ComponentIDs needed by each system.
 	systemUses            [][]componentID   // Slice of ComponentIDs used by each system.
 	systemComponentIDs    [][]componentID   // Slice of ComponentIDs needed or used by each system.
-	systemComponents      [][][]interface{} // Slice of components for matching entities.
 	systemComponentFields [][]reflect.Value // Slice of component struct fields used by each system.
 
 	systemReceivesUpdate []bool
@@ -76,8 +75,6 @@ type world struct {
 
 	cacheTime time.Duration
 
-	ctx *context
-
 	entityMutex    sync.Mutex
 	componentMutex sync.Mutex
 
@@ -93,8 +90,6 @@ func newWorld() *world {
 		haveSystemComponentName: make(map[string]bool),
 	}
 
-	w.ctx = &context{}
-
 	// Pad slices to match IDs starting with 1.
 	w.components = append(w.components, nil)
 	w.systemComponentNames = append(w.systemComponentNames, "")
@@ -113,7 +108,6 @@ func AddSystem(system System) {
 	w.systemReceivesUpdate = append(w.systemReceivesUpdate, true)
 	w.systemReceivesDraw = append(w.systemReceivesDraw, true)
 	w.systemEntities = append(w.systemEntities, nil)
-	w.systemComponents = append(w.systemComponents, nil)
 	w.systemComponentFields = append(w.systemComponentFields, nil)
 
 	w.entityMutex.Lock()
@@ -175,28 +169,25 @@ func AddSystemAfter(system System, after ...System) {
 }
 */
 
-func (w *world) setSystemComponentFields(i int) {
+func (w *world) setSystemComponentFields(e Entity, i int) {
 	//log.Println(len(w.systemComponentFields[i]))
 	//log.Println(w.systemComponentFields[i])
 	for j, field := range w.systemComponentFields[i] {
 		//log.Println(j, field, field.String())
 		id := w.systemComponentIDs[i][j]
 		//log.Println("SYSTEM", i, "FIELD", j, "ID", id)
-		if w.ctx.components[id] == nil {
+		if w.components[e][id] == nil {
 			field.Set(reflect.Zero(field.Type()))
 		} else {
-			field.Set(reflect.ValueOf(w.ctx.components[id]))
+			field.Set(reflect.ValueOf(w.components[e][id]))
 		}
 	}
 }
 
 func (w *world) updateSystem(i int) (int, error) {
-	w.ctx.systemIndex = i
-	w.ctx.allowed = w.systemComponentIDs[i]
 	updated := 0
 	for _, entity := range w.systemEntities[i] {
-		w.ctx.components = w.systemComponents[i][entity]
-		w.setSystemComponentFields(i)
+		w.setSystemComponentFields(entity, i)
 
 		err := w.systems[i].Update(entity)
 		if err != nil {
@@ -220,7 +211,6 @@ func (w *world) _handleRemovedEntities() {
 			for j, e := range w.systemEntities[i] {
 				if e == entity {
 					w.systemEntities[i] = _removeAt(w.systemEntities[i], j)
-					w.systemComponents[i][entity] = w.systemComponents[i][entity][:0] // TODO Could this lead to memory issues?
 					continue REMOVED
 				}
 			}
@@ -247,15 +237,6 @@ func (w *world) _handleModifiedEntities() {
 		w.handledModifiedEntities[entity] = true
 
 		for i := range w.systems {
-			l := len(w.systemComponents[i])
-			if l != int(w.maxEntityID+1) {
-				w.systemComponents[i] = append(w.systemComponents[i], make([][]interface{}, int(w.maxEntityID+1)-l)...)
-			}
-
-			if len(w.systemComponents[i][entity]) != int(w.maxComponentID+1) {
-				w.systemComponents[i][entity] = make([]interface{}, w.maxComponentID+1)
-			}
-
 			systemEntityIndex := -1
 			for j, systemEntity := range w.systemEntities[i] {
 				if systemEntity == entity {
@@ -271,15 +252,8 @@ func (w *world) _handleModifiedEntities() {
 					skip = true
 					break
 				}
-
-				w.systemComponents[i][entity][componentID] = c
 			}
 			if !skip {
-				for _, componentID := range w.systemUses[i] {
-					c := entity.getComponent(componentID)
-					w.systemComponents[i][entity][componentID] = c
-				}
-
 				if systemEntityIndex != -1 {
 					// Already attached.
 					continue
@@ -293,8 +267,6 @@ func (w *world) _handleModifiedEntities() {
 			} else if systemEntityIndex != -1 {
 				// Detach from system.
 				w.systemEntities[i] = _removeAt(w.systemEntities[i], systemEntityIndex)
-
-				w.systemComponents[i][entity] = w.systemComponents[i][entity][:0] // TODO Could this lead to memory issues?
 			}
 		}
 	}
@@ -362,12 +334,9 @@ func CurrentUpdates() int {
 }
 
 func (w *world) drawSystem(i int, screen *ebiten.Image) (int, error) {
-	w.ctx.systemIndex = i
-	w.ctx.allowed = w.systemComponentIDs[i]
 	var drawn int
 	for _, entity := range w.systemEntities[i] {
-		w.ctx.components = w.systemComponents[i][entity]
-		w.setSystemComponentFields(i)
+		w.setSystemComponentFields(entity, i)
 
 		err := w.systems[i].Draw(entity, screen)
 		if err != nil {