diff --git a/README b/README
index 0d658c333f1328b423851031c5b5d202f43df3c2..bec538bfc35239945d60487d66ed2e02b5d363a2 100644
--- a/README
+++ b/README
@@ -15,25 +15,26 @@ Usage: swift [OPTION]... PARAMFILE
        swift_mpi [OPTION]... PARAMFILE
 
 Valid options are:
-  -a          Pin runners using processor affinity
-  -c          Run with cosmological time integration
-  -C          Run with cooling
+  -a          Pin runners using processor affinity.
+  -c          Run with cosmological time integration.
+  -C          Run with cooling.
   -d          Dry run. Read the parameter file, allocate memory but does not read 
               the particles from ICs and exit before the start of time integration.
               Allows user to check validy of parameter and IC files as well as memory limits.
-  -D          Always drift all particles even the ones far from active particles.
-  -e          Enable floating-point exceptions (debugging mode)
-  -f    {int} Overwrite the CPU frequency (Hz) to be used for time measurements
-  -g          Run with an external gravitational potential
-  -G          Run with self-gravity
+  -D          Always drift all particles even the ones far from active particles. This emulates
+  	      Gadget-[23] and GIZMO's default behaviours.
+  -e          Enable floating-point exceptions (debugging mode).
+  -f    {int} Overwrite the CPU frequency (Hz) to be used for time measurements.
+  -g          Run with an external gravitational potential.
+  -G          Run with self-gravity.
   -n    {int} Execute a fixed number of time steps. When unset use the time_end parameter to stop. 
-  -s          Run with SPH
-  -S          Run with stars
+  -s          Run with hydrodynamics.
+  -S          Run with stars.
   -t    {int} The number of threads to use on each MPI rank. Defaults to 1 if not specified.
   -v     [12] Increase the level of verbosity
   	      1: MPI-rank 0 writes
 	      2: All MPI-ranks write
-  -y    {int} Time-step frequency at which task graphs are dumped
-  -h          Print this help message and exit
+  -y    {int} Time-step frequency at which task graphs are dumped.
+  -h          Print this help message and exit.
 
 See the file examples/parameter_example.yml for an example of parameter file.
diff --git a/examples/main.c b/examples/main.c
index 3c1f4aab261bd7e031a42d408f4275d766948e86..7ad8b9fdbd66e7181d790919290a56cc66a2fe40 100644
--- a/examples/main.c
+++ b/examples/main.c
@@ -57,9 +57,9 @@ void print_help_message() {
   printf("       swift_mpi [OPTION]... PARAMFILE\n\n");
 
   printf("Valid options are:\n");
-  printf("  %2s %8s %s\n", "-a", "", "Pin runners using processor affinity");
-  printf("  %2s %8s %s\n", "-c", "", "Run with cosmological time integration");
-  printf("  %2s %8s %s\n", "-C", "", "Run with cooling");
+  printf("  %2s %8s %s\n", "-a", "", "Pin runners using processor affinity.");
+  printf("  %2s %8s %s\n", "-c", "", "Run with cosmological time integration.");
+  printf("  %2s %8s %s\n", "-C", "", "Run with cooling.");
   printf(
       "  %2s %8s %s\n", "-d", "",
       "Dry run. Read the parameter file, allocate memory but does not read ");
@@ -70,29 +70,32 @@ void print_help_message() {
          "Allows user to check validy of parameter and IC files as well as "
          "memory limits.");
   printf("  %2s %8s %s\n", "-D", "",
-         "Always drift all particles even the ones far from active particles.");
+         "Always drift all particles even the ones far from active particles. "
+         "This emulates");
+  printf("  %2s %8s %s\n", "", "",
+         "Gadget-[23] and GIZMO's default behaviours.");
   printf("  %2s %8s %s\n", "-e", "",
-         "Enable floating-point exceptions (debugging mode)");
+         "Enable floating-point exceptions (debugging mode).");
   printf("  %2s %8s %s\n", "-f", "{int}",
-         "Overwrite the CPU frequency (Hz) to be used for time measurements");
+         "Overwrite the CPU frequency (Hz) to be used for time measurements.");
   printf("  %2s %8s %s\n", "-g", "",
-         "Run with an external gravitational potential");
-  printf("  %2s %8s %s\n", "-F", "", "Run with feedback ");
-  printf("  %2s %8s %s\n", "-G", "", "Run with self-gravity");
+         "Run with an external gravitational potential.");
+  printf("  %2s %8s %s\n", "-F", "", "Run with feedback.");
+  printf("  %2s %8s %s\n", "-G", "", "Run with self-gravity.");
   printf("  %2s %8s %s\n", "-n", "{int}",
          "Execute a fixed number of time steps. When unset use the time_end "
          "parameter to stop.");
-  printf("  %2s %8s %s\n", "-s", "", "Run with SPH");
-  printf("  %2s %8s %s\n", "-S", "", "Run with stars");
+  printf("  %2s %8s %s\n", "-s", "", "Run with hydrodynamics.");
+  printf("  %2s %8s %s\n", "-S", "", "Run with stars.");
   printf("  %2s %8s %s\n", "-t", "{int}",
          "The number of threads to use on each MPI rank. Defaults to 1 if not "
          "specified.");
-  printf("  %2s %8s %s\n", "-v", "[12]", "Increase the level of verbosity");
+  printf("  %2s %8s %s\n", "-v", "[12]", "Increase the level of verbosity.");
   printf("  %2s %8s %s\n", "", "", "1: MPI-rank 0 writes ");
   printf("  %2s %8s %s\n", "", "", "2: All MPI-ranks write");
   printf("  %2s %8s %s\n", "-y", "{int}",
-         "Time-step frequency at which task graphs are dumped");
-  printf("  %2s %8s %s\n", "-h", "", "Print this help message and exit");
+         "Time-step frequency at which task graphs are dumped.");
+  printf("  %2s %8s %s\n", "-h", "", "Print this help message and exit.");
   printf(
       "\nSee the file parameter_example.yml for an example of "
       "parameter file.\n");