Every time you gain a level, two wall segments are destroyed and Golem monsters will appear in their place. These golem monsters are equal level to you. This means they are not worth any bonus experience. You can ignore them or fight them like any other monster.
Plants and Spoons
Every time you kill a plant in the Rock Garden, a spoon will drop on to the ground. This small item grants +1 base damage. Individually spoons are quite weak, but you can acquire up to fifteen spoons in this manner for a whopping +15 base damage. Although this will occupy three inventory slots, for a melee-oriented class this is well worthwhile.
Plants created by the Earthmother's boons do not drop spoons. Similarly plants removed by her "clearance" boon will not leave spoons behind. Combined with the fact that she will block off many passages with her plants, this makes the Earthmother a horrible deity choice for the Rock Garden. Similarly, these spoons are incredibly powerful benefits to melee-type characters and will quickly fill your inventory. This means there will be little space for other items. As a result, Taurog is also a poor deity choice on the Rock Garden level.
The Rock Garden has a total of three bosses. There is one random boss, and the Brothers of Earth and Stone. The brothers are individually the two weakest bosses in the game, with only about 200 HP each. The challenge they present is that one has 75% magic resistance, and the other has 75% physical resistance. This generally means that you must have a different strategy for approaching both of these bosses.
Although three bosses may appear daunting, in practice you will get a large amount of XP and gold after each one you defeat. Because the bosses are individually quite weak, this is actually one of the easiest of the hard-difficulty levels. The trick is gaining momentum and being versatile enough to take on bosses with vastly different strengths and weaknesses.
Binlor is an excellent deity for this level, clearing out wall segments and lowering resistances of the boss monsters. If you purchase his Stone Heart boon several times, the brothers become laughable opponents. Similarly, the BYSSEPS glyph can be very useful for whittling away those resists. Remember that the physical resist boss can be poisoned easily (unlike regular golems which have a 50% chance for poison to fail) so he can be whittle away with hit and run tactics once you're strong enough to survive a single attack. Remember that spoons increase the damage of the PISORF glyph, and that this spell deals physical damage, making it very effective against the magic-resist boss.
Although the presence of a 75% physical resist boss may appear to preclude a physical specialist approach, there are ways to get around this. You will need to prepare the Really Big Sword, which increases your damage enormously against enemies with physical resist. Because this dungeon has goo blobs and wraiths, your RBS will get a lot of use even before the boss battles. Physical specialists benefit enormously from the spoons on the Rock Garden and as a result are basically home clear after they defeat the physical-resist boss. The HALPMEH glyph is extremely helpful here. Although it may be tempting to worship Taurog as a physical damage specialist, all the extra spoons in your inventory means you will have no space for his items, so he provides little benefit.
Because of the downsides of the Really Big Sword, you must make a strong effort to fight higher-level monsters. The sword causes all monsters to always get first strike against you, so weaker monsters (especially if you're poisoned) can quickly whittle you down. However, since higher-level monsters get first strike anyways, the sword is of no consequence so long as you focus on fighting those enemies. Once you have defeated the physical resist boss, you can convert the really big sword to get rid of the penalty.
Recommended classes for this approach are the Paladin, Warlord, Thief, and Assassin. Because of all the spoons that are present on this level, the Orc is generally not as favourable as the human. The HP->Attack preparation is strongly advised, even for humans. Because your base attack will be so high from all the spoons you collect, raising your attack bonus is far more beneficial than it usually is.
A hybrid character mixes spellcasting and physical attack power. This character will use his spellcasting ability against the physical resist boss, and his physical prowess against the magic-resist boss.
Because the BURNDAYRAZ glyph will be ineffective against the magic-resist boss, you will need to find a second glyph to help you out. The HALPMEH glyph and PISORF glyph are the two best options to fulfill this role, but CYDSTEPP and BYSSEPS will also work in a pinch. Remember that PISORF's damage is proportional to your base attack, which is boosted by those spoons. Pick up as many spoons as possible!
Against the physical resist boss, your melee attack won't be of much help and most of your damage will need to come from fireball. It will take you 7-9 castings of BURNDAYRAZ (depending on your level) to kill this boss. Using APHEELSIK to poison him and prevent regeneration means you can probably just kill him with hit and run tactics, and this will work very effectively if you also have the BLUDTUPOWA glyph. Otherwise, a mid-battle level-up and a few items to boost your mana should be sufficient.
The Crystal Ball is strongly advised as a preparation if you are going this route. Try to charge it up as much as possible before each boss battle. You should either play as an Elf with the HP->Attack preparation, or as a human with the Attack->MP preparation in order to maximize the balance of your physical damage output and your mana capacity.
Recommended classes are Sorcerer, Bloodmage, Wizard, Assassin, Fighter, and Thief.
The most difficult approach to Rock Garden is as a specialist spellcaster. Although the physical resist boss should be easily dispatched by a well-equipped spellcaster, the magic resist boss will be a more serious challenge. Generally speaking, the easiest approach is just to play as a hybrid instead. It's easier to raise a wizard's weak attack power than it is to punch through a boss with magic alone. If you're determined to follow this route, you will need to either use the PISORF glyph to fight the magic-resist boss (this will take some luck, as PISORF has a roughly 33% chance of appearing), or find a way to dramatically lower his resistances. You will also have to deal with massive mana requirements. The BLUDTUPOWA glyph, piercing wand and crystal ball items, the schadenfreude potion, and an altar to either Mystera Annur or Binlor Ironshield will all help you enormously.
Overall this is a feasible approach, and if you have your heart set on playing a pure spellcaster it's entirely possible, but it's by far the most difficult path. The Elf Wizard is strongly recommended; for any other class, you're better off just playing a hybrid.