diff --git a/cmd/lambda/lambda.go b/cmd/lambda/lambda.go
index 2f9116e..af63446 100644
--- a/cmd/lambda/lambda.go
+++ b/cmd/lambda/lambda.go
@@ -6,7 +6,7 @@ import (
 
 	"git.maximhutz.com/max/lambda/internal/cli"
 	"git.maximhutz.com/max/lambda/internal/config"
-	"git.maximhutz.com/max/lambda/internal/executer"
+	"git.maximhutz.com/max/lambda/internal/engine"
 	"git.maximhutz.com/max/lambda/internal/explanation"
 	"git.maximhutz.com/max/lambda/internal/performance"
 	"git.maximhutz.com/max/lambda/internal/statistics"
@@ -15,8 +15,8 @@ import (
 	"git.maximhutz.com/max/lambda/pkg/saccharine"
 )
 
-// Run main application.
 func main() {
+	// Parse CLI arguments.
 	options, err := config.FromArgs()
 	cli.HandleError(err)
 
@@ -24,7 +24,8 @@ func main() {
 	logger.Info("using program arguments", "args", os.Args)
 	logger.Info("parsed CLI options", "options", options)
 
-	input, err := options.Source.Pull()
+	// Get input.
+	input, err := options.Source.Extract()
 	cli.HandleError(err)
 
 	// Parse tokens.
@@ -35,33 +36,46 @@ func main() {
 	// Turn tokens into syntax tree.
 	expression, err := saccharine.Parse(tokens)
 	cli.HandleError(err)
-	if options.Verbose {
-		logger.Info("parsed syntax tree", "tree", saccharine.Stringify(expression))
-	}
+	logger.Info("parsed syntax tree", "tree", saccharine.Stringify(expression))
 
+	// Compile expression to lambda calculus.
 	compiled := convert.SaccharineToLambda(expression)
-	if options.Verbose {
-		logger.Info("compiled lambda expression", "tree", lambda.Stringify(compiled))
-	}
+	logger.Info("compiled lambda expression", "tree", lambda.Stringify(compiled))
 
-	process := executer.New(options, &compiled)
+	// Create reduction engine.
+	process := engine.New(options, &compiled)
+
+	// If the user selected to track CPU performance, attach a profiler to the
+	// process.
 	if options.Profile != "" {
 		profiler := performance.Track(options.Profile)
 		process.On("start", profiler.Start)
 		process.On("end", profiler.End)
 	}
 
+	// If the user selected to produce a step-by-step explanation, attach an
+	// observer here.
 	if options.Explanation {
 		explanation.Track(process)
 	}
 
-	statistics := statistics.Track()
-	process.On("start", statistics.Start)
-	process.On("step", statistics.Step)
-	process.On("end", statistics.End)
+	// If the user opted to track statistics, attach a tracker here, too.
+	if options.Statistics {
+		statistics := statistics.Track()
+		process.On("start", statistics.Start)
+		process.On("step", statistics.Step)
+		process.On("end", statistics.End)
+	}
+
+	// If the user selected for verbose debug logs, attach a reduction tracker.
+	if options.Verbose {
+		process.On("step", func() {
+			logger.Info("reduction", "tree", lambda.Stringify(compiled))
+		})
+	}
 
 	process.Run()
 
+	// Return the final reduced result.
 	fmt.Println(lambda.Stringify(compiled))
-	fmt.Fprint(os.Stderr, statistics.Results.String())
 }
diff --git a/internal/config/config.go b/internal/config/config.go
index 75030fb..757f55b 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -1,9 +1,10 @@
 package config
 
-// Arguments given to program.
+// Configuration settings for the program.
 type Config struct {
 	Source      Source // The source code given to the program.
 	Verbose     bool   // Whether or not to print debug logs.
 	Explanation bool   // Whether or not to print an explanation of the reduction.
 	Profile     string // If not nil, print a CPU profile during execution.
+	Statistics  bool   // Whether or not to print statistics.
 }
diff --git a/internal/config/get_logger.go b/internal/config/get_logger.go
index 6f959ad..8880878 100644
--- a/internal/config/get_logger.go
+++ b/internal/config/get_logger.go
@@ -5,13 +5,14 @@ import (
 	"os"
 )
 
-// Define the correct logger for the program to use.
+// Returns a structured logger with the appropriate configurations.
 func (c Config) GetLogger() *slog.Logger {
-	var level slog.Level
+	// By default, only print out errors.
+	level := slog.LevelError
+
+	// If the user set the output to be "VERBOSE", return the debug logs.
 	if c.Verbose {
 		level = slog.LevelInfo
-	} else {
-		level = slog.LevelError
 	}
 
 	return slog.New(
diff --git a/internal/config/parse_from_args.go b/internal/config/parse_from_args.go
index 8b92d9f..9cbf870 100644
--- a/internal/config/parse_from_args.go
+++ b/internal/config/parse_from_args.go
@@ -7,13 +7,14 @@ import (
 
 // Extract the program configuration from the command-line arguments.
 func FromArgs() (*Config, error) {
-	// Parse flags.
+	// Relevant flags.
 	verbose := flag.Bool("v", false, "Verbosity. If set, the program will print logs.")
 	explanation := flag.Bool("x", false, "Explanation. Whether or not to show all reduction steps.")
+	statistics := flag.Bool("s", false, "Statistics. If set, the process will print various statistics about the run.")
 	profile := flag.String("p", "", "CPU profiling. If set, the program will run a performance profile during execution.")
 	flag.Parse()
 
-	// Parse non-flag arguments.
+	// There must only be one input argument.
 	if flag.NArg() == 0 {
 		return nil, fmt.Errorf("no input given")
 	} else if flag.NArg() > 1 {
@@ -25,7 +26,7 @@ func FromArgs() (*Config, error) {
 	if flag.Arg(0) == "-" {
 		source = StdinSource{}
 	} else {
-		source = StringSource{data: flag.Arg(0)}
+		source = StringSource{Data: flag.Arg(0)}
 	}
 
 	return &Config{
@@ -33,5 +34,6 @@ func FromArgs() (*Config, error) {
 		Verbose:     *verbose,
 		Explanation: *explanation,
 		Profile:     *profile,
+		Statistics:  *statistics,
 	}, nil
 }
diff --git a/internal/config/source.go b/internal/config/source.go
index 7e78a98..9996f0c 100644
--- a/internal/config/source.go
+++ b/internal/config/source.go
@@ -5,21 +5,21 @@ import (
 	"os"
 )
 
-// Defines the consumption of different types of input sources.
+// A method of extracting input from the user.
 type Source interface {
-	// Get the data.
-	Pull() (string, error)
+	// Fetch data from this source.
+	Extract() (string, error)
 }
 
-// A source coming from a string.
-type StringSource struct{ data string }
+// A source defined by a string.
+type StringSource struct{ Data string }
 
-func (s StringSource) Pull() (string, error) { return s.data, nil }
+func (s StringSource) Extract() (string, error) { return s.Data, nil }
 
-// A source coming from standard input.
+// A source pulling from standard input.
 type StdinSource struct{}
 
-func (s StdinSource) Pull() (string, error) {
+func (s StdinSource) Extract() (string, error) {
 	data, err := io.ReadAll(os.Stdin)
 	if err != nil {
 		return "", err
diff --git a/internal/executer/executer.go b/internal/engine/engine.go
similarity index 61%
rename from internal/executer/executer.go
rename to internal/engine/engine.go
index d3fa123..4ebbf8b 100644
--- a/internal/executer/executer.go
+++ b/internal/engine/engine.go
@@ -1,31 +1,26 @@
-package executer
+package engine
 
 import (
-	"log/slog"
-
 	"git.maximhutz.com/max/lambda/internal/config"
 	"git.maximhutz.com/max/lambda/pkg/emitter"
 	"git.maximhutz.com/max/lambda/pkg/lambda"
 )
 
-type Executor struct {
+type Engine struct {
 	Config     *config.Config
 	Expression *lambda.Expression
 	emitter.Emitter
 }
 
-func New(config *config.Config, expression *lambda.Expression) *Executor {
-	return &Executor{Config: config, Expression: expression}
+func New(config *config.Config, expression *lambda.Expression) *Engine {
+	return &Engine{Config: config, Expression: expression}
 }
 
-func (e Executor) Run() {
+func (e Engine) Run() {
 	e.Emit("start")
 
 	for lambda.ReduceOnce(e.Expression) {
 		e.Emit("step")
-		if e.Config.Verbose {
-			slog.Info("reduction", "tree", lambda.Stringify(*e.Expression))
-		}
 	}
 
 	e.Emit("end")
diff --git a/internal/explanation/tracker.go b/internal/explanation/tracker.go
index 9e9ef98..48ee5b0 100644
--- a/internal/explanation/tracker.go
+++ b/internal/explanation/tracker.go
@@ -3,15 +3,15 @@ package explanation
 import (
 	"fmt"
 
-	"git.maximhutz.com/max/lambda/internal/executer"
+	"git.maximhutz.com/max/lambda/internal/engine"
 	"git.maximhutz.com/max/lambda/pkg/lambda"
 )
 
 type Tracker struct {
-	process *executer.Executor
+	process *engine.Engine
 }
 
-func Track(process *executer.Executor) *Tracker {
+func Track(process *engine.Engine) *Tracker {
 	tracker := &Tracker{process: process}
 	process.On("start", tracker.Start)
 	process.On("step", tracker.Step)
diff --git a/internal/statistics/tracker.go b/internal/statistics/tracker.go
index c1e2d20..0f4b4ff 100644
--- a/internal/statistics/tracker.go
+++ b/internal/statistics/tracker.go
@@ -1,13 +1,14 @@
 package statistics
 
 import (
+	"fmt"
+	"os"
 	"time"
 )
 
 type Tracker struct {
-	start   time.Time
-	steps   uint64
-	Results *Results
+	start time.Time
+	steps uint64
 }
 
 func Track() *Tracker {
@@ -17,7 +18,6 @@ func Track() *Tracker {
 func (t *Tracker) Start() {
 	t.start = time.Now()
 	t.steps = 0
-	t.Results = nil
 }
 
 func (t *Tracker) Step() {
@@ -25,8 +25,10 @@ func (t *Tracker) Step() {
 }
 
 func (t *Tracker) End() {
-	t.Results = &Results{
+	results := Results{
 		StepsTaken:  t.steps,
 		TimeElapsed: uint64(time.Since(t.start).Milliseconds()),
 	}
+
+	fmt.Fprint(os.Stderr, results.String())
 }