diff --git a/crates/core/src/main.rs b/crates/core/src/main.rs
index ab90e76..982997c 100644
--- a/crates/core/src/main.rs
+++ b/crates/core/src/main.rs
@@ -13,7 +13,8 @@ use alloy::{
 };
 use anyhow::Context;
 use clap::Parser;
-use futures::StreamExt;
+use futures::stream::futures_unordered::FuturesUnordered;
+use futures::{Stream, StreamExt};
 use revive_dt_common::iterators::FilesWithExtensionIterator;
 use revive_dt_node_interaction::EthereumNode;
 use semver::Version;
@@ -61,7 +62,7 @@ struct Test {
 }
 
 /// This represents the results that we gather from running test cases.
-type CaseResult = Result<Option<usize>, anyhow::Error>;
+type CaseResult = Result<usize, anyhow::Error>;
 
 fn main() -> anyhow::Result<()> {
     let args = init_cli()?;
@@ -144,7 +145,7 @@ where
 {
     let (report_tx, report_rx) = mpsc::unbounded_channel::<(Test, CaseResult)>();
 
-    let tests = prepare_tests::<L, F>(metadata_files);
+    let tests = prepare_tests::<L, F>(args, metadata_files);
     let driver_task = start_driver_task::<L, F>(args, tests, span, report_tx)?;
     let status_reporter_task = start_reporter_task(report_rx);
 
@@ -153,7 +154,10 @@ where
     Ok(())
 }
 
-fn prepare_tests<L, F>(metadata_files: &[MetadataFile]) -> impl Iterator<Item = Test>
+fn prepare_tests<'args, L, F>(
+    args: &'args Arguments,
+    metadata_files: &[MetadataFile],
+) -> impl Stream<Item = Test>
 where
     L: Platform,
     F: Platform,
@@ -235,11 +239,49 @@ where
                 case: case.clone(),
             }
         })
+        .map(async |test| test)
+        .collect::<FuturesUnordered<_>>()
+        .filter_map(async move |test| {
+            // Check that both compilers support this test, else we skip it
+            let is_supported = does_compiler_support_mode::<L>(args, &test.mode).await.ok().unwrap_or(false) &&
+                does_compiler_support_mode::<F>(args, &test.mode).await.ok().unwrap_or(false);
+
+            tracing::warn!(
+                metadata_file_path = %test.path.display(),
+                case_idx = %test.case_idx,
+                case_name = ?test.case.name,
+                mode = %test.mode,
+                "Skipping test as one or both of the compilers don't support it"
+            );
+
+            // We filter_map to avoid needing to clone `test`, but return it as-is.
+            if is_supported {
+                Some(test)
+            } else {
+                None
+            }
+        })
+}
+
+async fn does_compiler_support_mode<P: Platform>(
+    args: &Arguments,
+    mode: &Mode,
+) -> anyhow::Result<bool> {
+    let compiler_version_or_requirement = mode.compiler_version_to_use(args.solc.clone());
+    let compiler_path =
+        P::Compiler::get_compiler_executable(args, compiler_version_or_requirement).await?;
+    let compiler_version = P::Compiler::new(compiler_path.clone()).version()?;
+
+    Ok(P::Compiler::supports_mode(
+        &compiler_version,
+        mode.optimize_setting,
+        mode.pipeline,
+    ))
 }
 
 fn start_driver_task<L, F>(
     args: &Arguments,
-    tests: impl Iterator<Item = Test>,
+    tests: impl Stream<Item = Test>,
     span: Span,
     report_tx: mpsc::UnboundedSender<(Test, CaseResult)>,
 ) -> anyhow::Result<impl Future<Output = ()>>
@@ -254,7 +296,7 @@ where
     let compilation_cache = Arc::new(RwLock::new(HashMap::new()));
     let number_concurrent_tasks = args.number_of_concurrent_tasks();
 
-    Ok(futures::stream::iter(tests).for_each_concurrent(
+    Ok(tests.for_each_concurrent(
         // We want to limit the concurrent tasks here because:
         //
         // 1. We don't want to overwhelm the nodes with too many requests, leading to responses timing out.
@@ -309,14 +351,12 @@ async fn start_reporter_task(mut report_rx: mpsc::UnboundedReceiver<(Test, CaseR
 
     const GREEN: &str = "\x1B[32m";
     const RED: &str = "\x1B[31m";
-    const GRAY: &str = "\x1B[90m";
     const COLOUR_RESET: &str = "\x1B[0m";
     const BOLD: &str = "\x1B[1m";
     const BOLD_RESET: &str = "\x1B[22m";
 
     let mut number_of_successes = 0;
     let mut number_of_failures = 0;
-    let mut number_of_ignored = 0;
     let mut failures = vec![];
 
     // Wait for reports to come from our test runner. When the channel closes, this ends.
@@ -327,18 +367,12 @@ async fn start_reporter_task(mut report_rx: mpsc::UnboundedReceiver<(Test, CaseR
         let test_mode = test.mode.clone();
 
         match case_result {
-            Ok(Some(_inputs)) => {
+            Ok(_inputs) => {
                 number_of_successes += 1;
                 eprintln!(
                     "{GREEN}Case Succeeded:{COLOUR_RESET} {test_path} -> {case_name}:{case_idx} (mode: {test_mode})"
                 );
             }
-            Ok(None) => {
-                number_of_ignored += 1;
-                eprintln!(
-                    "{GRAY}Case Ignored:{COLOUR_RESET} {test_path} -> {case_name}:{case_idx} (mode: {test_mode})"
-                );
-            }
             Err(err) => {
                 number_of_failures += 1;
                 eprintln!(
@@ -372,8 +406,8 @@ async fn start_reporter_task(mut report_rx: mpsc::UnboundedReceiver<(Test, CaseR
 
     // Summary at the end.
     eprintln!(
-        "{} cases: {GREEN}{number_of_successes}{COLOUR_RESET} cases succeeded, {RED}{number_of_failures}{COLOUR_RESET} cases failed, {GRAY}{number_of_ignored}{COLOUR_RESET} cases ignored in {} seconds",
-        number_of_successes + number_of_failures + number_of_ignored,
+        "{} cases: {GREEN}{number_of_successes}{COLOUR_RESET} cases succeeded, {RED}{number_of_failures}{COLOUR_RESET} cases failed in {} seconds",
+        number_of_successes + number_of_failures,
         elapsed.as_secs()
     );
 }
@@ -390,14 +424,14 @@ async fn handle_case_driver<L, F>(
     leader_node: &L::Blockchain,
     follower_node: &F::Blockchain,
     _: Span,
-) -> anyhow::Result<Option<usize>>
+) -> anyhow::Result<usize>
 where
     L: Platform,
     F: Platform,
     L::Blockchain: revive_dt_node::Node + Send + Sync + 'static,
     F::Blockchain: revive_dt_node::Node + Send + Sync + 'static,
 {
-    let Some(leader_pre_link_contracts) = get_or_build_contracts::<L>(
+    let leader_pre_link_contracts = get_or_build_contracts::<L>(
         metadata,
         metadata_file_path,
         mode.clone(),
@@ -405,11 +439,8 @@ where
         compilation_cache.clone(),
         &HashMap::new(),
     )
-    .await?
-    else {
-        return Ok(None);
-    };
-    let Some(follower_pre_link_contracts) = get_or_build_contracts::<F>(
+    .await?;
+    let follower_pre_link_contracts = get_or_build_contracts::<F>(
         metadata,
         metadata_file_path,
         mode.clone(),
@@ -417,10 +448,7 @@ where
         compilation_cache.clone(),
         &HashMap::new(),
     )
-    .await?
-    else {
-        return Ok(None);
-    };
+    .await?;
 
     let mut leader_deployed_libraries = HashMap::new();
     let mut follower_deployed_libraries = HashMap::new();
@@ -581,7 +609,7 @@ where
                 cache.remove(&follower_key);
             }
 
-            let Some(leader_post_link_contracts) = get_or_build_contracts::<L>(
+            let leader_post_link_contracts = get_or_build_contracts::<L>(
                 metadata,
                 metadata_file_path,
                 mode.clone(),
@@ -589,11 +617,8 @@ where
                 compilation_cache.clone(),
                 &leader_deployed_libraries,
             )
-            .await?
-            else {
-                return Ok(None);
-            };
-            let Some(follower_post_link_contracts) = get_or_build_contracts::<F>(
+            .await?;
+            let follower_post_link_contracts = get_or_build_contracts::<F>(
                 metadata,
                 metadata_file_path,
                 mode.clone(),
@@ -601,10 +626,7 @@ where
                 compilation_cache,
                 &follower_deployed_libraries,
             )
-            .await?
-            else {
-                return Ok(None);
-            };
+            .await?;
 
             (leader_post_link_contracts, follower_post_link_contracts)
         } else {
@@ -631,7 +653,7 @@ where
         leader_state,
         follower_state,
     );
-    driver.execute().await.map(Some)
+    driver.execute().await
 }
 
 async fn get_or_build_contracts<P: Platform>(
@@ -641,7 +663,7 @@ async fn get_or_build_contracts<P: Platform>(
     config: &Arguments,
     compilation_cache: CompilationCache,
     deployed_libraries: &HashMap<ContractInstance, (Address, JsonAbi)>,
-) -> anyhow::Result<Option<Arc<(Version, CompilerOutput)>>> {
+) -> anyhow::Result<Arc<(Version, CompilerOutput)>> {
     let key = (
         metadata_file_path.to_path_buf(),
         mode.clone(),
@@ -652,25 +674,22 @@ async fn get_or_build_contracts<P: Platform>(
         match *compilation_artifact {
             Some(ref compiled_contracts) => {
                 tracing::debug!(?key, "Compiled contracts cache hit");
-                return Ok(Some(compiled_contracts.clone()));
+                return Ok(compiled_contracts.clone());
             }
             None => {
                 tracing::debug!(?key, "Compiled contracts cache miss");
-                let Some(compiled_contracts) = compile_contracts::<P>(
+                let compiled_contracts = compile_contracts::<P>(
                     metadata,
                     metadata_file_path,
                     &mode,
                     config,
                     deployed_libraries,
                 )
-                .await?
-                else {
-                    return Ok(None);
-                };
+                .await?;
                 let compiled_contracts = Arc::new(compiled_contracts);
 
                 *compilation_artifact = Some(compiled_contracts.clone());
-                return Ok(Some(compiled_contracts.clone()));
+                return Ok(compiled_contracts.clone());
             }
         }
     };
@@ -684,21 +703,18 @@ async fn get_or_build_contracts<P: Platform>(
     };
     let mut compilation_artifact = mutex.lock().await;
 
-    let Some(compiled_contracts) = compile_contracts::<P>(
+    let compiled_contracts = compile_contracts::<P>(
         metadata,
         metadata_file_path,
         &mode,
         config,
         deployed_libraries,
     )
-    .await?
-    else {
-        return Ok(None);
-    };
+    .await?;
     let compiled_contracts = Arc::new(compiled_contracts);
 
     *compilation_artifact = Some(compiled_contracts.clone());
-    Ok(Some(compiled_contracts.clone()))
+    Ok(compiled_contracts.clone())
 }
 
 async fn compile_contracts<P: Platform>(
@@ -707,22 +723,12 @@ async fn compile_contracts<P: Platform>(
     mode: &Mode,
     config: &Arguments,
     deployed_libraries: &HashMap<ContractInstance, (Address, JsonAbi)>,
-) -> anyhow::Result<Option<(Version, CompilerOutput)>> {
+) -> anyhow::Result<(Version, CompilerOutput)> {
     let compiler_version_or_requirement = mode.compiler_version_to_use(config.solc.clone());
     let compiler_path =
         P::Compiler::get_compiler_executable(config, compiler_version_or_requirement).await?;
     let compiler_version = P::Compiler::new(compiler_path.clone()).version()?;
 
-    if !P::Compiler::supports_mode(&compiler_version, mode.optimize_setting, mode.pipeline) {
-        tracing::info!(
-            %compiler_version,
-            metadata_file_path = %metadata_file_path.display(),
-            mode = ?mode,
-            "Skipping compilation: compiler does not support this mode or version"
-        );
-        return Ok(None);
-    }
-
     tracing::info!(
         %compiler_version,
         metadata_file_path = %metadata_file_path.display(),
@@ -759,7 +765,7 @@ async fn compile_contracts<P: Platform>(
 
     let compiler_output = compiler.try_build(compiler_path).await?;
 
-    Ok(Some((compiler_version, compiler_output)))
+    Ok((compiler_version, compiler_output))
 }
 
 async fn execute_corpus(