diff --git a/gnovm/cmd/gno/run.go b/gnovm/cmd/gno/run.go
index f0c4a1fb290..2c8d8c77350 100644
--- a/gnovm/cmd/gno/run.go
+++ b/gnovm/cmd/gno/run.go
@@ -2,7 +2,12 @@ package main
 
 import (
 	"context"
+	"errors"
 	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
 
 	gno "github.com/gnolang/gno/gnovm/pkg/gnolang"
 	"github.com/gnolang/gno/gnovm/tests"
@@ -12,6 +17,7 @@ import (
 type runCfg struct {
 	verbose bool
 	rootDir string
+	expr    string
 }
 
 func newRunCmd(io *commands.IO) *commands.Command {
@@ -44,6 +50,13 @@ func (c *runCfg) RegisterFlags(fs *flag.FlagSet) {
 		"",
 		"clone location of github.com/gnolang/gno (gnodev tries to guess it)",
 	)
+
+	fs.StringVar(
+		&c.expr,
+		"expr",
+		"main()",
+		"value of expression to evaluate. Defaults to executing function main() with no args",
+	)
 }
 
 func execRun(cfg *runCfg, args []string, io *commands.IO) error {
@@ -67,23 +80,87 @@ func execRun(cfg *runCfg, args []string, io *commands.IO) error {
 		testStore.SetLogStoreOps(true)
 	}
 
+	if len(args) == 0 {
+		args = []string{"."}
+	}
+
+	// read files
+	files, err := parseFiles(args)
+	if err != nil {
+		return err
+	}
+
+	if len(files) == 0 {
+		return errors.New("no files to run")
+	}
+
 	m := gno.NewMachineWithOptions(gno.MachineOptions{
-		PkgPath: "main",
+		PkgPath: string(files[0].PkgName),
 		Output:  stdout,
 		Store:   testStore,
 	})
 
 	defer m.Release()
 
-	// read files
-	files := make([]*gno.FileNode, len(args))
-	for i, fname := range args {
-		files[i] = gno.MustReadFile(fname)
-	}
-
 	// run files
 	m.RunFiles(files...)
-	m.RunMain()
+	runExpr(m, cfg.expr)
 
 	return nil
 }
+
+func parseFiles(fnames []string) ([]*gno.FileNode, error) {
+	files := make([]*gno.FileNode, 0, len(fnames))
+	for _, fname := range fnames {
+		if s, err := os.Stat(fname); err == nil && s.IsDir() {
+			subFns, err := listNonTestFiles(fname)
+			if err != nil {
+				return nil, err
+			}
+			subFiles, err := parseFiles(subFns)
+			if err != nil {
+				return nil, err
+			}
+			files = append(files, subFiles...)
+			continue
+		} else if err != nil {
+			// either not found or some other kind of error --
+			// in either case not a file we can parse.
+			return nil, err
+		}
+		files = append(files, gno.MustReadFile(fname))
+	}
+	return files, nil
+}
+
+func listNonTestFiles(dir string) ([]string, error) {
+	fs, err := os.ReadDir(dir)
+	if err != nil {
+		return nil, err
+	}
+	fn := make([]string, 0, len(fs))
+	for _, f := range fs {
+		n := f.Name()
+		if isGnoFile(f) &&
+			!strings.HasSuffix(n, "_test.gno") &&
+			!strings.HasPrefix(n, "_filetest.gno") {
+			fn = append(fn, filepath.Join(dir, n))
+		}
+	}
+	return fn, nil
+}
+
+func runExpr(m *gno.Machine, expr string) {
+	defer func() {
+		if r := recover(); r != nil {
+			fmt.Printf("panic running expression %s: %v\n%s\n",
+				expr, r, m.String())
+			panic(r)
+		}
+	}()
+	ex, err := gno.ParseExpr(expr)
+	if err != nil {
+		panic(fmt.Errorf("could not parse: %w", err))
+	}
+	m.Eval(ex)
+}
diff --git a/gnovm/cmd/gno/run_test.go b/gnovm/cmd/gno/run_test.go
index bccd7d1190c..e439a6bad8d 100644
--- a/gnovm/cmd/gno/run_test.go
+++ b/gnovm/cmd/gno/run_test.go
@@ -13,20 +13,57 @@ func TestRunApp(t *testing.T) {
 			stdoutShouldContain: "hello world!",
 		},
 		{
-			args:                 []string{"run", "../../tests/integ/run-main/"},
-			recoverShouldContain: "read ../../tests/integ/run-main/: is a directory", // FIXME: should work
+			args:                []string{"run", "../../tests/integ/run-main/"},
+			stdoutShouldContain: "hello world!",
+		},
+		{
+			args:             []string{"run", "../../tests/integ/does-not-exist"},
+			errShouldContain: "no such file or directory",
+		},
+		{
+			args:                []string{"run", "../../tests/integ/run-namedpkg/main.gno"},
+			stdoutShouldContain: "hello, other world!",
+		},
+		{
+			args:                 []string{"run", "../../tests/integ/run-package"},
+			recoverShouldContain: "name main not declared",
+		},
+		{
+			args:                []string{"run", "-expr", "Hello()", "../../tests/integ/run-package"},
+			stdoutShouldContain: "called Hello",
+		},
+		{
+			args:                []string{"run", "-expr", "World()", "../../tests/integ/run-package"},
+			stdoutShouldContain: "called World",
+		},
+		{
+			args:                []string{"run", "-expr", "otherFile()", "../../tests/integ/run-package"},
+			stdoutShouldContain: "hello from package2.gno",
+		},
+		{
+			args: []string{
+				"run", "-expr", "otherFile()",
+				"../../tests/integ/run-package/package.gno",
+			},
+			recoverShouldContain: "name otherFile not declared",
+		},
+		{
+			args: []string{
+				"run", "-expr", "otherFile()",
+				"../../tests/integ/run-package/package.gno",
+				"../../tests/integ/run-package/package2.gno",
+			},
+			stdoutShouldContain: "hello from package2.gno",
 		},
 		{
-			args:                 []string{"run", "../../tests/integ/does-not-exist"},
-			recoverShouldContain: "open ../../tests/integ/does-not-exist: no such file or directory",
+			args:                []string{"run", "-expr", "WithArg(1)", "../../tests/integ/run-package"},
+			stdoutShouldContain: "one",
 		},
 		{
-			args:                 []string{"run", "../../tests/integ/run-namedpkg/main.gno"},
-			recoverShouldContain: "expected package name [main] but got [namedpkg]", // FIXME: should work
+			args:                []string{"run", "-expr", "WithArg(-255)", "../../tests/integ/run-package"},
+			stdoutShouldContain: "out of range!",
 		},
-		// TODO: multiple files
 		// TODO: a test file
-		// TODO: a file without main
 		// TODO: args
 		// TODO: nativeLibs VS stdlibs
 		// TODO: with gas meter
diff --git a/gnovm/tests/integ/run-namedpkg/main.gno b/gnovm/tests/integ/run-namedpkg/main.gno
index 1fe31ed6549..0f1a2476004 100644
--- a/gnovm/tests/integ/run-namedpkg/main.gno
+++ b/gnovm/tests/integ/run-namedpkg/main.gno
@@ -1,5 +1,5 @@
 package namedpkg
 
 func main() {
-	println("hello world!")
+	println("hello, other world!")
 }
diff --git a/gnovm/tests/integ/run-package/package.gno b/gnovm/tests/integ/run-package/package.gno
new file mode 100644
index 00000000000..ebf4ccf4ec4
--- /dev/null
+++ b/gnovm/tests/integ/run-package/package.gno
@@ -0,0 +1,26 @@
+package pkg
+
+func Hello() {
+	println("called Hello")
+}
+
+func World() {
+	println("called World")
+}
+
+func hello() {
+	println("called hello")
+}
+
+func WithArg(i int) {
+	switch i {
+	case 0:
+		println("zero")
+	case 1:
+		println("one")
+	case 2:
+		println("two")
+	default:
+		println("out of range! :S")
+	}
+}
diff --git a/gnovm/tests/integ/run-package/package2.gno b/gnovm/tests/integ/run-package/package2.gno
new file mode 100644
index 00000000000..7b8b1ae6b31
--- /dev/null
+++ b/gnovm/tests/integ/run-package/package2.gno
@@ -0,0 +1,5 @@
+package pkg
+
+func otherFile() {
+	println("hello from package2.gno!")
+}