Sieging enemy

[Cv0]

How to destroy enemy (AI) that is heavily entrenched? They have lots of production structures, and all tiles filled with units. I have lots of units of my own, but its impossible to get past the narrow point. It takes a few turns to kill their units at that small point, by then they would reinforce the positions.

[Hyuhjhih]

All sieges are pretty vulnerable to flying units(except hwacha). So if you have tiefighter bought, spare a 5+10(1) turn to make one. Or you can even use a bunch of ornithopers with 5+5(1) turn and destroy the heavily cornered sieges.
Btw , is the AI in a campaign map or a skirmish player vs AI map.

[Cv0]

Campaign map. I play it first for gems. By the time my units get to the enemy TCs, they have multiple workers and multiple fortress towers etc and lots of units. I could mass flyers or siege units and brute force through the enemy, but im aiming for 3 stars for gems, so i dont have all the time to amass too many flyers. as for ground units, an army wont get through because the choke point is too small. enemy has quick reinforcements, so its a never ending battle.

[Endru1241]

Try conversion tactic.
It's very effective for deeling with choke points.
Get 3 high priest in siege tower. X2 if needed.

Another thing is fighting for space - very cheap units or even better (if possible) some cheap, preferably 1 turn structure that only takes space should be build/moved to any free space.
Make it as hard as possible for enemy to move around choke point tiles. And remove your cheap units/buildings if needed on the next turn.
Sometimes even better for fighting over tiles is taking advantage of existing enemy buildings or enemy units that are relatively less dangerous. It's almost a must in prison planet campaign.
If there is a huge number of production buildings in tight space - it's more effective to leave e.g. barracks or archery, to work like indestructible barrier (as long as you have unit on the other side - enemy cannot pass through it to attack from that side.