It might be interesting if we had some "critical hit" implemented, which deals
more damage than normal hits. Special addons could increase the chance for the
player to do such a hit.

at line 687 of bullets.c:
There is handled the hit at robots. There can be a random function that get a
float number. If this number is lower or equal to tux critical rate, instead of
using the normal method, us use a copy of this, but this time, multiply the
damage numbers in, by example, 1.2 (20% more!).

To bots have a critical rate, it would be difficult, but the "hit tux" is at
line 610 of the same file(src/bullet.c).

This implement a critical hit, the only problem is that tux critical hit would
need be manipuled by other functions, like

CONTINUATION:

(ignore the "like").
The major problem is that rand() function is not reliable. This function repeat
the numbers, resulting always in the same sequence of critical hits. So, the
greatest problem would be finding a substitute for rand() function.

rand(), apparently, can be changed by MyRandom(). It was used by influ.c in line
496 when tux is stuck. I never tested :P

Extending this report, there can be also a "graze" chance. Preferably for ranged
weapons only, based on melee hit chance.
(That is, when a melee attack would miss, a ranged attack graze)

Or on hindsight, maybe it would be better for the game to just grant 100% acc
for everything and everyone, and use the miss as graze (deals half damage)

Because our average weapon power, I do advise that critical increase damage only
in 20%. For initial feature implementation (as a simplification) the dex state
can be used, but the formula will need to be different. In long-term it may be
not-interesting to make it dependent on dex (balance reasons). Maybe physical or
strength are more suitable, because "with a strong body you can easily overpower
your opponents."