This comic has great concept. Mouse kingdom trying to thrive, while being harassed by bigger animals. Very good idea, i feel like a kid after reading Hobbit. Dreaming about world that don't exist.
Setting is nice. Few interesting surprises here and there.
Plot is serviceable. Could be more grim, or at least less plot armor - but Im still happy.
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it makes no sense for the mouse to build pitch roofs. Pitch roof is complicated construction used to mitigate the snow and rain load. It's especially not necessary, when the city is build inside a tree trunk !
If they all have chimneys they would choke on the smoke, if they don't burn them self down after few days anyway.
mouse weight 50 gram. They could literally stack one habitable cube on top of another, and the construction material - wood will sustain its weight even for a long span. They could use plants or spiders web to suspend some element to the ceiling.
this city should look more vertical build inside long cylinder.
this is locust tree. it must be ancient one if the trunk interiors are dead:
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different settlement - stronghold
Walls make sense to stop humans (if they were up to scale), who are very bad at climbing. but mouse? i saw mouse running upside down. Besides, the mouse could just jump over the wall, using the boulder on the left. Moreover this keep is build to protect from bigger animals, who are giants compare to mouse, they could just step inside or maybe devour mouse from top (like dog eating from the bowl).
"covered with thick layer of ivy" extra entanglement with plant make it even easier to breach the walls. But maybe it hides the settlement position a little from wandering animals.
how to make good mouse keep - go underground, dig a tunnel under a big boulder. I know then it could be flooded. But if you are smart mouse you would create a drain system. Or check where the ground has the best percolation. Or maybe go above ground level. The rock often has tiny tunnels, in the cracks. Even if you make a pile of boulders and live at the bottom of it, it would be a better fortress. Or maybe you could dig tunnels in chalk rock? Chalk cliff are quite common.