Challenge Mode

Challenge Mode

Video tutorial by Undead

Challenge Mode is a special feature added in the Peer Review DLC, allowing the player to compete with their friends for the lowest completion time and the least amount of placed portals in each level.

Least Portals

Main page: Least Portals

Unlocking Non-CM Levels

There are 11 levels in the singleplayer campaign that are not natively available in Challenge Mode. However, it is possible to get them with simple game file modification. Here's a step-by-step tutorial:

1. Open the game's directory (C:/Program Files (x86)/Steam/steamapps/common/Portal 2 by default).
2. Go to portal2_dlc1 folder and open the challenge_maplist.txt file.
3. Replace all of its content with the text below (triple click then Ctrl+C):

   "challenge_maps"{"sp"{"chapter_1"{"map""sp_a1_intro1""map""sp_a1_intro2""map""sp_a1_intro3""map""sp_a1_intro4""map""sp_a1_intro5""map""sp_a1_intro6""map""sp_a1_intro7""map""sp_a1_wakeup""map""sp_a2_intro"}"chapter_2"{"map""sp_a2_laser_intro""map""sp_a2_laser_stairs""map""sp_a2_dual_lasers""map""sp_a2_laser_over_goo""map""sp_a2_catapult_intro""map""sp_a2_trust_fling""map""sp_a2_pit_flings""map""sp_a2_fizzler_intro"}"chapter_3"{"map""sp_a2_sphere_peek""map""sp_a2_ricochet""map""sp_a2_bridge_intro""map""sp_a2_bridge_the_gap""map""sp_a2_turret_intro""map""sp_a2_laser_relays""map""sp_a2_turret_blocker""map""sp_a2_laser_vs_turret""map""sp_a2_pull_the_rug"}"chapter_4"{"map""sp_a2_column_blocker""map""sp_a2_laser_chaining""map""sp_a2_triple_laser""map""sp_a2_bts1""map""sp_a2_bts2"}"chapter_5"{"map""sp_a2_bts3""map""sp_a2_bts4""map""sp_a2_bts5""map""sp_a2_core"}"chapter_6"{"map""sp_a3_01""map""sp_a3_03""map""sp_a3_jump_intro""map""sp_a3_bomb_flings""map""sp_a3_crazy_box""map""sp_a3_transition01"}"chapter_7"{"map""sp_a3_speed_ramp""map""sp_a3_speed_flings""map""sp_a3_portal_intro""map""sp_a3_end"}"chapter_8"{"map""sp_a4_intro""map""sp_a4_tb_intro""map""sp_a4_tb_trust_drop""map""sp_a4_tb_wall_button""map""sp_a4_tb_polarity""map""sp_a4_tb_catch""map""sp_a4_stop_the_box""map""sp_a4_laser_catapult""map""sp_a4_laser_platform""map""sp_a4_speed_tb_catch""map""sp_a4_jump_polarity"}"chapter_9"{"map""sp_a4_finale1""map""sp_a4_finale2""map""sp_a4_finale3""map""sp_a4_finale4"}}"coop"{"chapter_1"{"map""mp_coop_doors""map""mp_coop_race_2""map""mp_coop_laser_2""map""mp_coop_rat_maze""map""mp_coop_laser_crusher""map""mp_coop_teambts"}"chapter_2"{"map""mp_coop_fling_3""map""mp_coop_infinifling_train""map""mp_coop_come_along""map""mp_coop_fling_1""map""mp_coop_catapult_1""map""mp_coop_multifling_1""map""mp_coop_fling_crushers""map""mp_coop_fan"}"chapter_3"{"map""mp_coop_wall_intro""map""mp_coop_wall_2""map""mp_coop_catapult_wall_intro""map""mp_coop_wall_block""map""mp_coop_catapult_2""map""mp_coop_turret_walls""map""mp_coop_turret_ball""map""mp_coop_wall_5"}"chapter_4"{"map""mp_coop_tbeam_redirect""map""mp_coop_tbeam_drill""map""mp_coop_tbeam_catch_grind_1""map""mp_coop_tbeam_laser_1""map""mp_coop_tbeam_polarity""map""mp_coop_tbeam_polarity2""map""mp_coop_tbeam_polarity3""map""mp_coop_tbeam_maze""map""mp_coop_tbeam_end"}"chapter_5"{"map""mp_coop_paint_come_along""map""mp_coop_paint_redirect""map""mp_coop_paint_bridge""map""mp_coop_paint_walljumps""map""mp_coop_paint_speed_fling""map""mp_coop_paint_red_racer""map""mp_coop_paint_speed_catch""map""mp_coop_paint_longjump_intro"}"chapter_6"{"map""mp_coop_separation_1""map""mp_coop_tripleaxis""map""mp_coop_catapult_catch""map""mp_coop_2paints_1bridge""map""mp_coop_paint_conversion""map""mp_coop_bridge_catch""map""mp_coop_laser_tbeam""map""mp_coop_paint_rat_maze""map""mp_coop_paint_crazy_box"}}}

4. After saving and restarting the game you should have access to missing levels.

Keep in mind that scores from these missing levels are not updated automatically on the CM leaderboard. Because of that, you have to submit scores manually. The in-game leaderboard, however, still works fine.