diff --git a/src/Command.mm b/src/Command.mm
index be5b754..d591c15 100644
--- a/src/Command.mm
+++ b/src/Command.mm
@@ -124,14 +124,15 @@ padArguments(OFArray<OFString *> *arguments, size_t count)
 		if (isDown) {
 			arguments = padArguments(arguments, 2);
 			return ((int(__cdecl *)(int))_function)(
-			    execute(arguments[1]));
+			    execute(arguments[1], isDown));
 		}
 		break;
 	case ARG_2EXP:
 		if (isDown) {
 			arguments = padArguments(arguments, 3);
 			return ((int(__cdecl *)(int, int))_function)(
-			    execute(arguments[1]), execute(arguments[2]));
+			    execute(arguments[1], isDown),
+			    execute(arguments[2], isDown));
 		}
 		break;
 	case ARG_1EST:
diff --git a/src/Cube.mm b/src/Cube.mm
index a35899b..85ed74c 100644
--- a/src/Cube.mm
+++ b/src/Cube.mm
@@ -296,7 +296,7 @@ VARP(minmillis, 0, 5, 1000);
 - (void)applicationWillTerminate:(OFNotification *)notification
 {
 	stop();
-	disconnect(true);
+	disconnect(true, false);
 	writecfg();
 	cleangl();
 	cleansound();
@@ -357,11 +357,17 @@ VARP(minmillis, 0, 5, 1000);
 }
 @end
 
+// failure exit
 void
-fatal(OFString *s, OFString *o) // failure exit
+fatal(OFConstantString *s, ...)
 {
-	OFString *msg =
-	    [OFString stringWithFormat:@"%@%@ (%s)\n", s, o, SDL_GetError()];
+	va_list args;
+	va_start(args, s);
+	OFMutableString *msg = [[OFMutableString alloc] initWithFormat:s
+	                                                     arguments:args];
+	va_end(args);
+
+	[msg appendFormat:@" (%s)\n", SDL_GetError()];
 
 	[Cube.sharedInstance showMessage:msg];
 	[OFApplication terminateWithStatus:1];
diff --git a/src/clientgame.mm b/src/clientgame.mm
index defd585..6a394b5 100644
--- a/src/clientgame.mm
+++ b/src/clientgame.mm
@@ -251,7 +251,7 @@ updateworld(int millis) // main game update loop
 		curtime = millis - lastmillis;
 		if (sleepwait && lastmillis > sleepwait) {
 			sleepwait = 0;
-			execute(sleepcmd);
+			execute(sleepcmd, true);
 		}
 		physicsframe();
 		checkquad(curtime);
@@ -445,11 +445,11 @@ selfdamage(int damage, int actor, DynamicEntity *act)
 		player1.state = CS_DEAD;
 		player1.pitch = 0;
 		player1.roll = 60;
-		playsound(S_DIE1 + rnd(2));
+		playsound(S_DIE1 + rnd(2), NULL);
 		spawnstate(player1);
 		player1.lastaction = lastmillis;
 	} else
-		playsound(S_PAIN6);
+		playsound(S_PAIN6, NULL);
 }
 
 void
diff --git a/src/clients.mm b/src/clients.mm
index fdc8384..995f900 100644
--- a/src/clients.mm
+++ b/src/clients.mm
@@ -94,7 +94,7 @@ writeclientinfo(OFStream *stream)
 void
 connects(OFString *servername)
 {
-	disconnect(1); // reset state
+	disconnect(true, false); // reset state
 	addserver(servername);
 
 	conoutf(@"attempting to connect to %@", servername);
@@ -113,12 +113,12 @@ connects(OFString *servername)
 		connattempts = 0;
 	} else {
 		conoutf(@"could not connect to server");
-		disconnect();
+		disconnect(false, false);
 	}
 }
 
 void
-disconnect(int onlyclean, int async)
+disconnect(bool onlyclean, bool async)
 {
 	if (clienthost) {
 		if (!connecting && !disconnecting) {
@@ -162,7 +162,7 @@ trydisconnect()
 	}
 	if (connecting) {
 		conoutf(@"aborting connection attempt");
-		disconnect();
+		disconnect(false, false);
 		return;
 	}
 	conoutf(@"attempting to disconnect...");
@@ -233,7 +233,7 @@ void
 server_err()
 {
 	conoutf(@"server network error, disconnecting...");
-	disconnect();
+	disconnect(false, false);
 }
 
 int lastupdate = 0, lastping = 0;
@@ -382,7 +382,7 @@ gets2c() // get updates from the server
 		++connattempts;
 		if (connattempts > 3) {
 			conoutf(@"could not connect to server");
-			disconnect();
+			disconnect(false, false);
 			return;
 		}
 	}
@@ -406,7 +406,7 @@ gets2c() // get updates from the server
 
 		case ENET_EVENT_TYPE_DISCONNECT:
 			if (disconnecting)
-				disconnect();
+				disconnect(false, false);
 			else
 				server_err();
 			return;
diff --git a/src/clients2c.mm b/src/clients2c.mm
index 1022dfa..06327ef 100644
--- a/src/clients2c.mm
+++ b/src/clients2c.mm
@@ -14,7 +14,7 @@ void
 neterr(OFString *s)
 {
 	conoutf(@"illegal network message (%@)", s);
-	disconnect();
+	disconnect(false, false);
 }
 
 void
@@ -67,7 +67,7 @@ localservertoclient(uchar *buf, int len)
 {
 	if (ENET_NET_TO_HOST_16(*(ushort *)buf) != len)
 		neterr(@"packet length");
-	incomingdemodata(buf, len);
+	incomingdemodata(buf, len, false);
 
 	uchar *end = buf + len;
 	uchar *p = buf + 2;
@@ -86,7 +86,7 @@ localservertoclient(uchar *buf, int len)
 				conoutf(@"you are using a different game "
 				        @"protocol (you: %d, server: %d)",
 				    PROTOCOL_VERSION, prot);
-				disconnect();
+				disconnect(false, false);
 				return;
 			}
 			toservermap = @"";
@@ -100,7 +100,7 @@ localservertoclient(uchar *buf, int len)
 			    strcmp(text, clientpassword.UTF8String)) {
 				conoutf(@"you need to set the correct password "
 				        @"to join this server!");
-				disconnect();
+				disconnect(false, false);
 				return;
 			}
 			if (getint(&p) == 1)
@@ -221,7 +221,7 @@ localservertoclient(uchar *buf, int len)
 			e.z = getint(&p) / DMF;
 			if (gun == GUN_SG)
 				createrays(&s, &e);
-			shootv(gun, &s, &e, d);
+			shootv(gun, &s, &e, d, false);
 			break;
 		}
 
diff --git a/src/commands.mm b/src/commands.mm
index c862470..e3e7e4a 100644
--- a/src/commands.mm
+++ b/src/commands.mm
@@ -123,7 +123,8 @@ parseexp(char *&p, int right)
 	if (left == '(') {
 		OFString *t;
 		@try {
-			t = [OFString stringWithFormat:@"%d", execute(@(s))];
+			t = [OFString
+			    stringWithFormat:@"%d", execute(@(s), true)];
 		} @finally {
 			free(s);
 		}
@@ -329,7 +330,7 @@ execfile(OFIRI *cfgfile)
 		return false;
 	}
 
-	execute(command);
+	execute(command, true);
 	return true;
 }
 
@@ -407,7 +408,7 @@ intset(OFString *name, int v)
 void
 ifthen(OFString *cond, OFString *thenp, OFString *elsep)
 {
-	execute((![cond hasPrefix:@"0"] ? thenp : elsep));
+	execute((![cond hasPrefix:@"0"] ? thenp : elsep), true);
 }
 
 void
@@ -418,22 +419,22 @@ loopa(OFString *times, OFString *body)
 	loopi(t)
 	{
 		intset(@"i", i);
-		execute(body);
+		execute(body, true);
 	}
 }
 
 void
 whilea(OFString *cond, OFString *body)
 {
-	while (execute(cond))
-		execute(body);
+	while (execute(cond, true))
+		execute(body, true);
 }
 
 void
 onrelease(bool on, OFString *body)
 {
 	if (!on)
-		execute(body);
+		execute(body, true);
 }
 
 void
diff --git a/src/console.mm b/src/console.mm
index e4be446..209c283 100644
--- a/src/console.mm
+++ b/src/console.mm
@@ -177,7 +177,7 @@ history(int n)
 
 	if (!rec && n >= 0 && n < vhistory.count) {
 		rec = true;
-		execute(vhistory[vhistory.count - n - 1]);
+		execute(vhistory[vhistory.count - n - 1], true);
 		rec = false;
 	}
 }
diff --git a/src/editing.mm b/src/editing.mm
index 5a2da60..0d7a047 100644
--- a/src/editing.mm
+++ b/src/editing.mm
@@ -37,7 +37,7 @@ bool selset = false;
 			sqr *s = S(sel->x + x, sel->y + y); \
 			b;                                  \
 		}                                           \
-		remip(sel);                                 \
+		remip(sel, 0);                              \
 	}
 
 int cx, cy, ch;
@@ -440,7 +440,7 @@ replace()
 		}
 	}
 	block b = { 0, 0, ssize, ssize };
-	remip(&b);
+	remip(&b, 0);
 }
 
 void
@@ -518,7 +518,7 @@ void
 setvdeltaxy(int delta, const block *sel)
 {
 	loopselxy(s->vdelta = max(s->vdelta + delta, 0));
-	remipmore(sel);
+	remipmore(sel, 0);
 }
 
 void
@@ -563,7 +563,7 @@ arch(int sidedelta, int _a)
 	              (y == 0 || y == sel->ys - 1 ? sidedelta : 0))
 	        : (archverts[sel->ys - 1][y] +
 	              (x == 0 || x == sel->xs - 1 ? sidedelta : 0)));
-	remipmore(sel);
+	remipmore(sel, 0);
 }
 
 void
@@ -581,7 +581,7 @@ slope(int xd, int yd)
 	// Ugly hack to make the macro work.
 	block *sel = sel_;
 	loopselxy(s->vdelta = xd * x + yd * y + off);
-	remipmore(sel);
+	remipmore(sel, 0);
 }
 
 void
@@ -596,7 +596,7 @@ perlin(int scale, int seed, int psize)
 	perlinarea(&sel, scale, seed, psize);
 	sel.xs++;
 	sel.ys++;
-	remipmore(&sel);
+	remipmore(&sel, 0);
 	sel.xs--;
 	sel.ys--;
 }
diff --git a/src/entities.mm b/src/entities.mm
index 2ec7f86..08c9c8e 100644
--- a/src/entities.mm
+++ b/src/entities.mm
@@ -54,7 +54,7 @@ renderentities()
 			        (float)S(e.x, e.y)->floor + mmi.zoff + e.attr3,
 			        e.y),
 			    (float)((e.attr1 + 7) - (e.attr1 + 7) % 15), 0,
-			    false, 1.0f, 10.0f, mmi.snap);
+			    false, 1.0f, 10.0f, mmi.snap, 0);
 		} else {
 			if (OUTBORD(e.x, e.y))
 				continue;
diff --git a/src/protos.h b/src/protos.h
index eb079a5..bf44f27 100644
--- a/src/protos.h
+++ b/src/protos.h
@@ -7,7 +7,7 @@ extern void setvar(OFString *name, int i);
 extern int getvar(OFString *name);
 extern bool identexists(OFString *name);
 extern bool addcommand(OFString *name, void (*fun)(), int narg);
-extern int execute(OFString *p, bool down = true);
+extern int execute(OFString *p, bool down);
 extern void exec(OFString *cfgfile);
 extern bool execfile(OFIRI *cfgfile);
 extern void resetcomplete();
@@ -71,7 +71,7 @@ extern void setarraypointers();
 // client
 extern void localservertoclient(uchar *buf, int len);
 extern void connects(OFString *servername);
-extern void disconnect(int onlyclean = 0, int async = 0);
+extern void disconnect(bool onlyclean, bool async);
 extern void toserver(OFString *text);
 extern void addmsg(int rel, int num, int type, ...);
 extern bool multiplayer();
@@ -114,10 +114,10 @@ extern void renderscores();
 // world
 extern void setupworld(int factor);
 extern void empty_world(int factor, bool force);
-extern void remip(const block *b, int level = 0);
-extern void remipmore(const block *b, int level = 0);
+extern void remip(const block *b, int level);
+extern void remipmore(const block *b, int level);
 extern int closestent();
-extern int findentity(int type, int index = 0);
+extern int findentity(int type, int index);
 extern void trigger(int tag, int type, bool savegame);
 extern void resettagareas();
 extern void settagareas();
@@ -141,7 +141,7 @@ extern void computeraytable(float vx, float vy);
 extern int isoccluded(float vx, float vy, float cx, float cy, float csize);
 
 // main
-extern void fatal(OFString *s, OFString *o = @"");
+extern void fatal(OFConstantString *s, ...);
 
 // rendertext
 extern void draw_text(OFString *string, int left, int top, int gl_num);
@@ -160,7 +160,7 @@ extern void edittypexy(int type, const block *sel);
 extern void edittexxy(int type, int t, const block *sel);
 extern void editheightxy(bool isfloor, int amount, const block *sel);
 extern bool noteditmode();
-extern void pruneundos(int maxremain = 0);
+extern void pruneundos(int maxremain);
 
 // renderextras
 extern void line(int x1, int y1, float z1, int x2, int y2, float z2);
@@ -188,7 +188,7 @@ extern void load_world(OFString *mname);
 extern void writemap(OFString *mname, int msize, uchar *mdata);
 extern OFData *readmap(OFString *mname);
 extern void loadgamerest();
-extern void incomingdemodata(uchar *buf, int len, bool extras = false);
+extern void incomingdemodata(uchar *buf, int len, bool extras);
 extern void demoplaybackstep();
 extern void stop();
 extern void stopifrecording();
@@ -203,7 +203,7 @@ extern void setentphysics(int mml, int mmr);
 extern void physicsframe();
 
 // sound
-extern void playsound(int n, const OFVector3D *loc = NULL);
+extern void playsound(int n, const OFVector3D *loc);
 extern void playsoundc(int n);
 extern void initsound();
 extern void cleansound();
@@ -211,7 +211,7 @@ extern void cleansound();
 // rendermd2
 extern void rendermodel(OFString *mdl, int frame, int range, int tex, float rad,
     OFVector3D position, float yaw, float pitch, bool teammate, float scale,
-    float speed, int snap = 0, int basetime = 0);
+    float speed, int snap, int basetime);
 @class MapModelInfo;
 extern MapModelInfo *getmminfo(int i);
 
@@ -237,10 +237,10 @@ extern void sendmaps(int n, OFString *mapname, int mapsize, uchar *mapdata);
 extern ENetPacket *recvmap(int n);
 
 // weapon
-extern void selectgun(int a = -1, int b = -1, int c = -1);
+extern void selectgun(int a, int b, int c);
 extern void shoot(DynamicEntity *d, const OFVector3D *to);
 extern void shootv(int gun, const OFVector3D *from, const OFVector3D *to,
-    DynamicEntity *d = 0, bool local = false);
+    DynamicEntity *d, bool local);
 extern void createrays(const OFVector3D *from, const OFVector3D *to);
 extern void moveprojectiles(float time);
 extern void projreset();
diff --git a/src/rendermd2.mm b/src/rendermd2.mm
index 0d09a07..b5043ac 100644
--- a/src/rendermd2.mm
+++ b/src/rendermd2.mm
@@ -23,7 +23,7 @@ delayedload(MD2 *m)
 
 		OFIRI *IRI1 = [baseIRI IRIByAppendingPathComponent:@"tris.md2"];
 		if (![m loadWithIRI:IRI1])
-			fatal(@"loadmodel: ", IRI1.string);
+			fatal(@"loadmodel: %@", IRI1.string);
 
 		OFIRI *IRI2 = [baseIRI IRIByAppendingPathComponent:@"skin.jpg"];
 		int xs, ys;
diff --git a/src/savegamedemo.mm b/src/savegamedemo.mm
index b7ef8bf..87a970c 100644
--- a/src/savegamedemo.mm
+++ b/src/savegamedemo.mm
@@ -351,7 +351,7 @@ stopreset()
 	conoutf(@"demo stopped (%d msec elapsed)", lastmillis - starttime);
 	stop();
 	[players removeAllObjects];
-	disconnect(0, 0);
+	disconnect(false, false);
 }
 
 VAR(demoplaybackspeed, 10, 100, 1000);
diff --git a/src/serverbrowser.mm b/src/serverbrowser.mm
index e520d3e..9bc0dcf 100644
--- a/src/serverbrowser.mm
+++ b/src/serverbrowser.mm
@@ -273,7 +273,7 @@ updatefrommaster()
 		conoutf(@"master server not replying");
 	else {
 		[servers removeAllObjects];
-		execute(@((char *)reply));
+		execute(@((char *)reply), true);
 	}
 	servermenu();
 }
diff --git a/src/serverutil.mm b/src/serverutil.mm
index 6f63c0d..8c95da0 100644
--- a/src/serverutil.mm
+++ b/src/serverutil.mm
@@ -140,10 +140,17 @@ localservertoclient(uchar *buf, int len)
 }
 
 void
-fatal(OFString *s, OFString *o)
+fatal(OFConstantString *s, ...)
 {
 	cleanupserver();
-	[OFStdOut writeFormat:@"servererror: %@\n", s];
+
+	va_list args;
+	va_start(args, s);
+	OFString *msg = [[OFString alloc] initWithFormat:s arguments:args];
+	va_end(args);
+
+	[OFStdOut writeFormat:@"servererror: %@\n", msg];
+
 	exit(1);
 }
 
diff --git a/src/sound.mm b/src/sound.mm
index 5f42cf4..cd2767a 100644
--- a/src/sound.mm
+++ b/src/sound.mm
@@ -159,7 +159,7 @@ void
 playsoundc(int n)
 {
 	addmsg(0, 2, SV_SOUND, n);
-	playsound(n);
+	playsound(n, NULL);
 }
 
 int soundsatonce = 0, lastsoundmillis = 0;
diff --git a/src/world.mm b/src/world.mm
index bd7c023..8b805ff 100644
--- a/src/world.mm
+++ b/src/world.mm
@@ -42,7 +42,7 @@ settag(int tag, int type)
 	}
 	block b = { minx, miny, maxx - minx + 1, maxy - miny + 1 };
 	if (maxx)
-		remip(&b); // remip minimal area of changed geometry
+		remip(&b, 0); // remip minimal area of changed geometry
 }
 
 void
@@ -70,13 +70,13 @@ trigger(int tag, int type, bool savegame)
 	settag(tag, type);
 
 	if (!savegame && type != 3)
-		playsound(S_RUMBLE);
+		playsound(S_RUMBLE, NULL);
 
 	OFString *aliasname =
 	    [OFString stringWithFormat:@"level_trigger_%d", tag];
 
 	if (identexists(aliasname))
-		execute(aliasname);
+		execute(aliasname, true);
 
 	if (type == 2)
 		endsp(false);
@@ -457,7 +457,7 @@ empty_world(int factor, bool force)
 	if (!force && noteditmode())
 		return;
 	cleardlights();
-	pruneundos();
+	pruneundos(0);
 	sqr *oldworld = world;
 	bool copy = false;
 	if (oldworld && factor < 0) {
@@ -516,7 +516,7 @@ empty_world(int factor, bool force)
 	if (oldworld) {
 		OFFreeMemory(oldworld);
 		toggleedit();
-		execute(@"fullbright 1");
+		execute(@"fullbright 1", true);
 	}
 }
 
diff --git a/src/worldio.mm b/src/worldio.mm
index b8ef9bb..792c584 100644
--- a/src/worldio.mm
+++ b/src/worldio.mm
@@ -262,7 +262,7 @@ load_world(OFString *mname) // still supports all map formats that have existed
 {
 	stopifrecording();
 	cleardlights();
-	pruneundos();
+	pruneundos(0);
 	setnames(mname);
 	gzFile f =
 	    gzopen([cgzname cStringWithEncoding:OFLocale.encoding], "rb9");
@@ -350,13 +350,10 @@ load_world(OFString *mname) // still supports all map formats that have existed
 			break;
 		}
 		default: {
-			if (type < 0 || type >= MAXTYPE) {
-				OFString *t = [OFString
-				    stringWithFormat:@"%d @ %d", type, k];
-				fatal(@"while reading map: type out of "
-				      @"range: ",
-				    t);
-			}
+			if (type < 0 || type >= MAXTYPE)
+				fatal(@"while reading map: type out of range: "
+				      @"%d @ %d",
+				    type, k);
 			s->type = type;
 			s->floor = gzgetc(f);
 			s->ceil = gzgetc(f);
diff --git a/src/worldlight.mm b/src/worldlight.mm
index 3db0001..d05b480 100644
--- a/src/worldlight.mm
+++ b/src/worldlight.mm
@@ -165,7 +165,7 @@ postlightarea(block &a) // median filter, smooths out random noise in light and
 		median(b);
 	}
 
-	remip(&a);
+	remip(&a, 0);
 }
 
 void
@@ -268,5 +268,5 @@ blockpaste(const block *b)
 	for (int x = b->x; x < b->xs + b->x; x++)
 		for (int y = b->y; y < b->ys + b->y; y++)
 			*S(x, y) = *q++;
-	remipmore(b);
+	remipmore(b, 0);
 }