--- supertux-0.1.3.orig/src/tile.cpp
+++ supertux-0.1.3/src/tile.cpp
@@ -99,7 +99,11 @@ void TileManager::load_tileset(std::stri
               tile->anim_speed = 25;
 
               LispReader reader(lisp_cdr(element));
+              #ifdef NDEBUG
+              void(reader.read_int("id",  &tile->id));
+              #else
               assert(reader.read_int("id",  &tile->id));
+              #endif
               reader.read_bool("solid",     &tile->solid);
               reader.read_bool("brick",     &tile->brick);
               reader.read_bool("ice",       &tile->ice);