diff --git a/algobattle/battle.py b/algobattle/battle.py
index 5fbb5b08..46f8b543 100644
--- a/algobattle/battle.py
+++ b/algobattle/battle.py
@@ -3,6 +3,7 @@
 This module contains the :class:`Battle` class, which speciefies how each type of battle is fought and scored,
 some basic battle types, and related classed.
 """
+
 from abc import abstractmethod
 from collections.abc import Iterable
 from dataclasses import dataclass, field
@@ -201,8 +202,7 @@ async def run(
         *,
         with_results: Literal[False] = False,
         **kwargs: Unpack[RunKwargs],
-    ) -> Fight:
-        ...
+    ) -> Fight: ...
 
     @overload
     async def run(
@@ -211,8 +211,7 @@ async def run(
         *,
         with_results: Literal[True],
         **kwargs: Unpack[RunKwargs],
-    ) -> tuple[Fight, GeneratorResult, SolverResult | None]:
-        ...
+    ) -> tuple[Fight, GeneratorResult, SolverResult | None]: ...
 
     async def run(
         self,
@@ -250,12 +249,7 @@ async def run(
             The resulting info about the executed fight, and the results if the flag has been set.
         """
         gen_result, sol_result = await self.run_raw(max_size=max_size, **kwargs)
-        if gen_result.instance is None or gen_result.solution is None:
-            score = 1
-        elif sol_result is None or sol_result.solution is None:
-            score = 0
-        else:
-            score = self.calculate_score(gen_result, sol_result)
+        score = self.calculate_score(gen_result, sol_result)
         fight = Fight.from_results(
             score=score,
             max_size=max_size,
@@ -321,7 +315,7 @@ async def run_raw(
         )
         return gen_result, sol_result
 
-    def calculate_score(self, gen_result: GeneratorResult, sol_result: SolverResult) -> float:
+    def calculate_score(self, gen_result: GeneratorResult, sol_result: SolverResult | None) -> float:
         """Calculates the score achieved by the solver in this fight.
 
         Both results need to contain all instance and/or solution data required.
@@ -333,9 +327,25 @@ def calculate_score(self, gen_result: GeneratorResult, sol_result: SolverResult)
         Returns:
             A number in [0, 1] with higher numbers meaning the solver performed better.
         """
-        assert gen_result.instance is not None
-        assert sol_result.solution is not None
+        # We first need to check whether the generator somehow failed. This can happen in three cases:
+        # it doesn't produce an instance, it creates an invalid instance or it doesn't create a needed solution
+        # note that gen_result.instance and gen_result.error will both contain data if the generator outputted an
+        # invalid instance and/or solution
+        if (
+            gen_result.instance is None
+            or gen_result.error is not None
+            or (self.problem.with_solution and gen_result.solution is None)
+        ):
+            return 1
+        # sol_result is None only if the generator failed, which needs to be caught by the above check
+        assert sol_result is not None
+        # The solver failed if it didn't output a solution or the solution contains some error
+        if sol_result.solution is None or sol_result.error is not None:
+            return 0
+
         if self.problem.with_solution:
+            # we need this assert since type checkers can't see the dependency between self.problem.with_solution
+            # and gen_result.solution that is created by the last check in the first "if"
             assert gen_result.solution is not None
             score = self.problem.score(
                 gen_result.instance, solver_solution=sol_result.solution, generator_solution=gen_result.solution
@@ -449,8 +459,7 @@ class FallbackConfig(Config):
 
         if TYPE_CHECKING:
             # to hint that we're gonna fill this with arbitrary data belonging to some supposed battle type
-            def __getattr__(self, attr: str, /) -> Any:
-                ...
+            def __getattr__(self, attr: str, /) -> Any: ...
 
     class UiData(BaseModel):
         """Object containing custom diplay data.
@@ -705,13 +714,13 @@ class Config(Battle.Config):
         """Number of fights that will be fought."""
         weighting: Annotated[float, Ge(0)] = 1.1
         """How much each successive fight should be weighted more than the previous."""
-        scores: set[Role] = {Role.generator, Role.solver} # noqa: RUF012
+        scores: set[Role] = {Role.generator, Role.solver}  # noqa: RUF012
         """Who to show each fight's scores to."""
-        instances: set[Role] = {Role.generator, Role.solver} # noqa: RUF012
+        instances: set[Role] = {Role.generator, Role.solver}  # noqa: RUF012
         """Who to show the instances to."""
-        generator_solutions: set[Role] = {Role.generator} # noqa: RUF012
+        generator_solutions: set[Role] = {Role.generator}  # noqa: RUF012
         """Who to show the generator's solutions to, if the problem requires them."""
-        solver_solutions: set[Role] = {Role.solver} # noqa: RUF012
+        solver_solutions: set[Role] = {Role.solver}  # noqa: RUF012
         """Who to show the solver's solutions to."""
 
     class UiData(Battle.UiData):
diff --git a/pyproject.toml b/pyproject.toml
index 7ebbc91a..da89458d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "pdm.backend"
 
 [project]
 name = "algobattle-base"
-version = "4.3.3"
+version = "4.3.4"
 description = "The Algobattle lab course package."
 readme = "README.md"
 requires-python = ">=3.11"
diff --git a/uv.lock b/uv.lock
index 1b241d91..fd46aa9d 100644
--- a/uv.lock
+++ b/uv.lock
@@ -4,7 +4,7 @@ requires-python = ">=3.11"
 
 [[package]]
 name = "algobattle-base"
-version = "4.3.2"
+version = "4.3.4"
 source = { editable = "." }
 dependencies = [
     { name = "anyio" },