My group just played through "First Blood" and "A Fat Goblin" last night. I, as the Overlord, lost horribly at every turn: no goblins escaped, no crops were stolen and Splig didn't find his target until he had already taken 8/13 damage and failed two interrogate checks.
I was feeling pretty disheartened last night, especially since it took us 4.5 hours to do all that and it was obvious I was going to lose each encounter by the heroes' second turn. I don't feel quite so bad this morning since three of the heroes are first edition veterans and the fourth was taking their suggestions while I've only played the first quest from first edition once.
My biggest "victory" was the Tripwire card and it didn't slow them down any.
My biggest problem, by far, is one of the heroes (Ashrian) whose ability stuns all minion monsters that start their activation adjacent to her and the player took the Disciple class for healing and whose starting weapon has a stun effect. The players' tactic consists of rushing Ashrian into the biggest pack of minions (and with the narrow corridors it's easy to have most of an entire group adjacent to her) while the remaining heroes massacre the rest.
Here is how "First Blood" went:
Heroes' turn 1: Scout kills master goblin archer with ranged attack. Ashrian has enough movement to get next to EVERY REMAINING goblin archer (all minions crammed into that back corner) and locks them down with her passive. She then uses her feat and stuns both ettins. The bloodthirsty dwarf then bum rushes at the stunned ettins (can't remember if he got in melee range or not). Necromancer casually strolls up.
Overlord's turn 2: Summon dead goblin archer. Draw card (nothing useful). Activate ettins and spend "action" removing Stun effect. Activate goblins, minions are immediately Stunned because they are next to Ashrian, use Scamper on Master goblin to move through everyone and then take a shot at Ashrian (doing 2/10 damage).
Heroes' turn 2: Scout uses range to kill fleeing master goblin and then moves behind Ashrian to serve as a human shield. Dwarf "fatigue moves" to Mauler and double attacks. Necromancer summons Familiar. Ashrian does nothing.
Overlord's turn 2: Summon dead goblin (again). Draw Dash card (monster gets extra move action). Dash + Scamper master goblin. Attack with goblin did nothing noteworthy and is making haste for the exit, minions are still stunned thanks to Ashrian's ability. Mauler beats on dwarf. Second ettin moves to the middle of the map and throws Scout aside so I can attack Ashrian next turn using Reach ability.
Heroes' turn 3: Ashrian "fatigue moves," hits ettin but fails to trigger weapon's Stun effect, fatigue moves back to keep goblins Stunned. Neromancer and familiar kill ettin. Dwarf and Scout gang up and kill Mauler. Encounter ends.
Both encounters for "A Fat Goblin" went the same way except drawn out because the maps required the heroes to move further and/or store crops. The end result was that small rooms and smaller corridors meant that monster groups were Stunned and destroyed like an assembly line. Reinforcements were too far away to get to the heroes before the current group was wiped out and the heroes had turned to face the newcomers.
Damage to the heroes was either healed by Ashrian, taken as fatigue by the Scout, rofled at by the dwarf because I did a whopping two damage and he could take another four hits like that before being worried (but still standing). The Necromancer kept to the back and used her familiar to kill monsters in one hit or assist another hero in killing something that didn't go down immediately.