diff --git a/rogueviz/nilrider/nilrider.cpp b/rogueviz/nilrider/nilrider.cpp
index d695999e..e5057a84 100644
--- a/rogueviz/nilrider/nilrider.cpp
+++ b/rogueviz/nilrider/nilrider.cpp
@@ -168,6 +168,7 @@ bool turn(int delta) {
   }
 
 void main_menu();
+void layer_selection_screen();
 
 #define PSEUDOKEY_PAUSE 2511
 #define PSEUDOKEY_SIM 2512
@@ -221,6 +222,9 @@ void run() {
   if(planning_mode && !view_replay) {
     for(auto& b: buttons) show_button(b.first, b.second, planmode == b.first ? 0xFFD500 : dialog::dialogcolor);
     show_button(PSEUDOKEY_SIM, "simulation");
+    if(curlev->sublevels.size() && layer_edited) {
+      show_button('L', "layer: " + layer_edited->name);
+      }
     }
   
   bool pause_av = view_replay || !planning_mode;
@@ -248,6 +252,10 @@ void run() {
   dialog::add_key_action(PSEUDOKEY_SIM, toggle_replay);
   dialog::display();
 
+  if(planning_mode && !view_replay && curlev->sublevels.size()) {
+    dialog::add_key_action('L', [] { pushScreen(layer_selection_screen); });
+    }
+
   int* t = scfg_nilrider.keyaction;
   for(int i=1; i<512; i++) {
     auto& ka = dialog::key_actions;
@@ -291,6 +299,20 @@ void pick_level() {
   dialog::display();
   }
 
+void layer_selection_screen() {
+  poly_outline = 0xFF;
+  dialog::init(XLAT("layer selection"), 0xC0C0FFFF, 150, 100);
+  dialog::addBreak(50);
+  auto layers = curlev->gen_layer_list();
+  char key = 'a';
+  for(auto l: layers) {
+    dialog::addBoolItem(l->name, l == layer_edited, key++);
+    dialog::add_action([l] { layer_edited = l; popScreen(); });
+    }
+  dialog::addBack();
+  dialog::display();
+  }
+
 void pick_game() {
   clearMessages();
   dialog::init();
diff --git a/rogueviz/nilrider/planning.cpp b/rogueviz/nilrider/planning.cpp
index aad98bf6..075bb2dc 100644
--- a/rogueviz/nilrider/planning.cpp
+++ b/rogueviz/nilrider/planning.cpp
@@ -2,17 +2,29 @@ namespace nilrider {
 
 hyperpoint get_spline(ld t);
 
+level *layer_edited;
+
 bool level::simulate() {
   loaded_or_planned = true;
   if(history.empty())
     history.push_back(start);
   auto at = history.back();
-  
+
   if(at.t >= isize(plan) - 1.001) return false;
   
   ld goal_t;
+
+  if(at.on_surface && isize(history) >= 2 && !history[isize(history)-2].on_surface) {
+    int index = ceil(history[isize(history)-2].t)+1;
+    if(index >= isize(plan)) {
+      return false;
+      }
+    plan[index].at = at.where;
+    history.back().t = at.t = index;
+    if(index == isize(plan) - 1) return false;
+    }
   
-  if(1) {
+  if(at.on_surface) {
     int steps = 20;
     ld min_t, max_t;
     
@@ -47,16 +59,22 @@ bool level::simulate() {
       }
     
     goal_t = (min_t + max_t) / 2;
-    }
 
-  hyperpoint h = get_spline(goal_t);
-  at.heading_angle = atan2(h[1] - at.where[1], h[0] - at.where[0]);
-  history.back() = at;
-  
-  at.be_consistent();
-  if(!at.tick(this)) return false;
-  at.t = goal_t;
-  history.push_back(at);
+    hyperpoint h = get_spline(goal_t);
+    at.heading_angle = atan2(h[1] - at.where[1], h[0] - at.where[0]);
+
+    history.back() = at;
+    at.be_consistent();
+    if(!at.tick(this)) { println(hlog, "tick returns false"); return false; }
+    at.t = goal_t;
+    history.push_back(at);
+    }
+  else {
+    at.be_consistent();
+    if(at.where[2] <= surface(at.where) - 100) { println(hlog, "fall"); return false; }
+    if(!at.tick(this)) { println(hlog, "crash"); return false; }
+    history.push_back(at);
+    }
   
   return true;
   }
@@ -95,6 +113,8 @@ void level::compute_plan_transform() {
 
 bool restored = false;
 
+int plan_precision = 50;
+
 void level::draw_planning_screen() {
   if(just_refreshing) return;
 
@@ -104,13 +124,14 @@ void level::draw_planning_screen() {
     new_levellines_for = mousept = current.where;
     }
   curlev->init_textures();
+  for(auto lay: gen_layer_list()) lay->init_textures();
   dynamicval<eGeometry> g(geometry, gEuclid);
   dynamicval<eModel> pm(pmodel, mdDisk);
   dynamicval<bool> ga(vid.always3, false);
   dynamicval<geometryinfo1> gi(ginf[gEuclid].g, giEuclid2);
   check_cgi();
   cgi.require_shapes();
-  curlev->init_shapes();
+  for(auto lay: gen_layer_list()) lay->init_shapes();
   initquickqueue();
   
   if(recompute_plan_transform) {
@@ -131,10 +152,20 @@ void level::draw_planning_screen() {
 
   box = inHighQual ? scr_to_map(hpxy(10, 0))[0] - scr_to_map(hpxy(0,0))[0] : scr_to_map(hpxy(mousex + 5, mousey))[0] - mousept[0];
   
-  /* draw the map */
-  auto& p = queuepolyat(T, shPlanFloor, 0xFFFFFFFF, PPR::FLOOR);
-  p.tinf = &uniltinf;
-  uniltinf.texture_id = unil_texture_levels->textureid;
+  auto draw_layer = [&] (level *l, color_t col) {
+    auto& p = queuepolyat(T, l->shPlanFloor, col, PPR::FLOOR);
+    p.tinf = &l->uniltinf;
+    l->uniltinf.texture_id = l->unil_texture_levels->textureid;
+    };
+
+  bool layer_found = false;
+  auto layers = gen_layer_list();
+  for(auto l: layers) {
+    if(l == layer_edited) layer_found = true;
+    else draw_layer(l, 0x808080FF);
+    }
+  if(!layer_found) layer_edited = this;
+  draw_layer(layer_edited, 0xFFFFFFFF);
   
   auto draw_sq = [&] (hyperpoint h, color_t col, PPR prio) {
     curvepoint(hpxy(h[0]+box, h[1]+box));
@@ -162,41 +193,45 @@ void level::draw_planning_screen() {
     draw_line(pp.at - pp.vel, pp.at + pp.vel, 0x80, PPR::BFLOOR);
     }
   
-  bool after = false;
-  
   if(history.empty()) history.push_back(start);
   
-  closest_t = history.back().t;
-  ld closest_dist = box * 2;
-
   vid.linewidth *= 3;
+
   int ps = isize(plan);
   for(int t=0; t<=100*(ps-1); t++) {
-    ld tt = t / 100.;
-    if(tt > history.back().t && !after) {
-      queuecurve(T, 0xFFFFFFC0, 0, PPR::LIZEYE);
-      after = true;
-      }
-    hyperpoint h = get_spline(tt);
+    hyperpoint h = get_spline(t / 100.);
     curvepoint(hpxy(h[0], h[1]));
-    ld dist = sqhypot_d(2, h - mousept);
-    if(dist < closest_dist) closest_dist = dist, closest_t = tt;
-    }
-  queuecurve(T, after ? 0xFF8080C0 : 0xFFFFFFC0, 0, PPR::LIZEYE);
-  vid.linewidth /= 3;  
-    
-  if(!history.empty()) {
-    int mint = 0, maxt = isize(history)-1;
-    while(mint < maxt) {
-      int t = (mint + maxt + 1) / 2;
-      if(history[t].t > closest_t) maxt = t-1;
-      else mint = t;
-      }
-      
-    current = history[mint];
     }
+  queuecurve(T, 0xFF8080C0, 0, PPR::LIZEYE);
+  vid.linewidth /= 3;
 
-  draw_sq(get_spline(closest_t), 0x8080FFFF, PPR::ITEM);
+  closest_t = history.back().t;
+  ld closest_dist = box * 2;
+  current = history.back();
+
+  vid.linewidth *= 3;
+  level *current_surface = this;
+  auto surface_color = [&] () -> color_t {
+    if(current_surface == layer_edited) return 0xFFFFFFFF;
+    if(current_surface) return 0x101010FF;
+    return 0xFF00FFFF;
+    };
+  for(int i=0; i<isize(history);) {
+    auto& hi = history[i];
+    auto& h = hi.where;
+    curvepoint(hpxy(h[0], h[1]));
+    if(hi.on_surface != current_surface) {
+      queuecurve(T, surface_color(), 0, PPR::LIZEYE);
+      current_surface = hi.on_surface;
+      curvepoint(hpxy(h[0], h[1]));
+      }
+    i++; if(i < isize(history)) i = min(i + plan_precision - 1, isize(history)-1);
+    ld dist = sqhypot_d(2, h - mousept);
+    if(dist < closest_dist) closest_dist = dist, current = history[i];
+    }
+  queuecurve(T, surface_color(), 0, PPR::LIZEYE);
+  vid.linewidth /= 3;
+    
   draw_sq(current.where, 0xFF8000FF, PPR::ITEM);
   draw_sq(mousept, 0x8080FFFF, PPR::ITEM);