This is getting serious!
This article contains spoilers. It might spoil your gaming experience when first playing these games.

Moon Mountains is the first secret level of Serious Sam: The First Encounter and Serious Sam HD: The First Encounter.


Sam has apparently, discovered the Moon Mountains, the source of the Nile. He must fight his way through to the location of the Fire Element.


  1. On the fourth mountain/platform, on the edge, you will notice some ammo, and a Super Armor floating down below the mountain/platform. If you stand around there, where the ammo was, the armor will be catapulted into the center of the mountain/platform.
  2. On the fifth mountain/platform, go to the edge, as close as possible, towards the waterfall. Jump across the waterfall to register the secret passage secret. This can also be done by 'rocket jumping', but it can be done without it. Note that, at least in the HD version of the game, it is also possible to trigger this secret without jumping through the waterfall. Following the normal route and exiting from the first cave normally spawns a batch of enemies that disables #2, however by staying near to the right-hand wall as you exit the cave (and moving toward #3), you can bypass the enemy trigger and walk along the ledge until you register the secret passage secret.
  3. From where you landed at #2 when jumping, go to the other edge of the waterfall, there is a Large Health there.
  4. After the circular waterfall, before jumping down on the small lake with the Reebans, jump across the square hall and touch the wall to reveal a secret cavern with ammo, and enemies (Kamikazes on lower difficulties, or a Highlander on Serious Difficulty).
  5. When you jump down the lake from the square hole from #4, from the doorway, turn left and go back into the water, behind some rocks is a secret Super Health.
  6. After the lake, when you can see the circular waterfall again (before the Highlander miniboss fight), turn around, and shoot a rocket above the entrance. This will enable a teleport that will lead you to the other edge of the "room".
  7. The teleport from #6 counts as a secret if used.

Enemy, item and weapon countEdit

EnemiesTourist and Easy singleplayer Normal singleplayerHard and Mental singleplayerSerious Difficulty singleplayerTourist co-op Easy and Normal co-opHard and Mental co-opSerious co-op
Beheaded Rocketeers44424442
Beheaded Bombers99959995
Beheaded Firecrackers11101110
Beheaded Kamikazes891415891415
Male Gnaars1927271119272711
Female Gnaars1014163010141630
Kleer skeletons1023264010232640
Marsh Hoppers3468757534687575
Scythian Witch-Harpies1542535515425355
Sirian Werebulls01130113
Juvenile Arachnoids11111111
Common Aludran Reptiloids1491414914
Highlander Aludran Reptiloids11121112
Reeban Electro-Fishes1616162016161620
Minor Bio-mechanoids48964896
Major Bio-mechanoids11171117
ItemsAll difficulties
Extra Small Health4
Small Health2
Medium Health8
Large Health3
Extra Small Armor4
Medium Armor3
Large Armor5
Extra Large Armor2
Super Armor2
WeaponsAll difficulties
M1-A2 Thompsons1
AmmunitionAll difficulties


  • In Serious Sam Xbox, each mountain platform has trees. In the PC version of Serious Sam 1, there are no trees.
  • The level is addressed as 'DreamWaterfalls' in the game's music files.
  • Since the leakage of the alpha prototype of Serious Sam, the first level of Water Planet was originally going to be Moon Mountains.