diff --git a/src/client/Main.ts b/src/client/Main.ts
index b9cadc34f..c45057e81 100644
--- a/src/client/Main.ts
+++ b/src/client/Main.ts
@@ -63,6 +63,7 @@ declare global {
   // Extend the global interfaces to include your custom events
   interface DocumentEventMap {
     "join-lobby": CustomEvent<JoinLobbyEvent>;
+    "kick-player": CustomEvent;
   }
 }
 
diff --git a/src/core/GameRunner.ts b/src/core/GameRunner.ts
index d2fd60c6e..2e8201240 100644
--- a/src/core/GameRunner.ts
+++ b/src/core/GameRunner.ts
@@ -4,6 +4,7 @@ import { Executor } from "./execution/ExecutionManager";
 import { WinCheckExecution } from "./execution/WinCheckExecution";
 import {
   AllPlayers,
+  Attack,
   Cell,
   Game,
   GameUpdates,
@@ -35,7 +36,7 @@ export async function createGameRunner(
   gameStart: GameStartInfo,
   clientID: ClientID,
   mapLoader: GameMapLoader,
-  callBack: (gu: GameUpdateViewData) => void,
+  callBack: (gu: GameUpdateViewData | ErrorUpdate) => void,
 ): Promise<GameRunner> {
   const config = await getConfig(gameStart.config, null);
   const gameMap = await loadGameMap(gameStart.config.gameMap, mapLoader);
@@ -231,7 +232,7 @@ export class GameRunner {
       throw new Error(`player with id ${playerID} not found`);
     }
 
-    const condition = (a) => a.id() === attackID;
+    const condition = (a: Attack) => a.id() === attackID;
     const attack =
       player.outgoingAttacks().find(condition) ??
       player.incomingAttacks().find(condition);
diff --git a/src/core/Schemas.ts b/src/core/Schemas.ts
index 735c2b9fd..0871acf9e 100644
--- a/src/core/Schemas.ts
+++ b/src/core/Schemas.ts
@@ -171,7 +171,7 @@ const TokenSchema = z
   .string()
   .refine(
     (v) =>
-      PersistentIdSchema.safeParse(v).success ||
+      PersistentIdSchema.safeParse(v).success ??
       JwtTokenSchema.safeParse(v).success,
     {
       message: "Token must be a valid UUID or JWT",
@@ -213,7 +213,11 @@ export const RequiredPatternSchema = z
         new PatternDecoder(val, base64url.decode);
         return true;
       } catch (e) {
-        console.error(JSON.stringify(e.message, null, 2));
+        if (e instanceof Error) {
+          console.error(JSON.stringify(e.message, null, 2));
+        } else {
+          console.error(String(e));
+        }
         return false;
       }
     },
diff --git a/src/core/execution/FakeHumanExecution.ts b/src/core/execution/FakeHumanExecution.ts
index b5920b5f7..828631757 100644
--- a/src/core/execution/FakeHumanExecution.ts
+++ b/src/core/execution/FakeHumanExecution.ts
@@ -350,7 +350,7 @@ export class FakeHumanExecution implements Execution {
     const dist = euclDistFN(tile, 25, false);
     let tileValue = targets
       .filter((unit) => dist(this.mg, unit.tile()))
-      .map((unit) => {
+      .map((unit): number => {
         switch (unit.type()) {
           case UnitType.City:
             return 25_000;
diff --git a/src/core/execution/PlayerExecution.ts b/src/core/execution/PlayerExecution.ts
index 913ea0c1d..db021bd7f 100644
--- a/src/core/execution/PlayerExecution.ts
+++ b/src/core/execution/PlayerExecution.ts
@@ -1,7 +1,7 @@
 import { Config } from "../configuration/Config";
 import { Execution, Game, Player, UnitType } from "../game/Game";
 import { GameImpl } from "../game/GameImpl";
-import { TileRef } from "../game/GameMap";
+import { GameMap, TileRef } from "../game/GameMap";
 import { calculateBoundingBox, getMode, inscribed, simpleHash } from "../Util";
 
 export class PlayerExecution implements Execution {
@@ -190,7 +190,11 @@ export class PlayerExecution implements Execution {
     }
 
     const firstTile = cluster.values().next().value;
-    const filter = (_, t: TileRef): boolean =>
+    if (!firstTile) {
+      return;
+    }
+
+    const filter = (_: GameMap, t: TileRef): boolean =>
       this.mg?.ownerID(t) === this.player?.smallID();
     const tiles = this.mg.bfs(firstTile, filter);
 
diff --git a/src/core/execution/SAMLauncherExecution.ts b/src/core/execution/SAMLauncherExecution.ts
index 484028aec..15891db07 100644
--- a/src/core/execution/SAMLauncherExecution.ts
+++ b/src/core/execution/SAMLauncherExecution.ts
@@ -1,6 +1,7 @@
 import {
   Execution,
   Game,
+  isUnit,
   MessageType,
   Player,
   Unit,
@@ -80,7 +81,9 @@ class SAMTargetingSystem {
       [UnitType.AtomBomb, UnitType.HydrogenBomb],
       ({ unit }) => {
         return (
-          unit.owner() !== this.player && !this.player.isFriendly(unit.owner())
+          isUnit(unit) &&
+          unit.owner() !== this.player &&
+          !this.player.isFriendly(unit.owner())
         );
       },
     );
@@ -212,6 +215,7 @@ export class SAMLauncherExecution implements Execution {
       this.MIRVWarheadSearchRadius,
       UnitType.MIRVWarhead,
       ({ unit }) => {
+        if (!isUnit(unit)) return false;
         if (unit.owner() === this.player) return false;
         if (this.player.isFriendly(unit.owner())) return false;
         const dst = unit.targetTile();
diff --git a/src/core/game/BinaryLoaderGameMapLoader.ts b/src/core/game/BinaryLoaderGameMapLoader.ts
index 2107b6faa..31e058026 100644
--- a/src/core/game/BinaryLoaderGameMapLoader.ts
+++ b/src/core/game/BinaryLoaderGameMapLoader.ts
@@ -31,7 +31,9 @@ export class BinaryLoaderGameMapLoader implements GameMapLoader {
       return cachedMap;
     }
 
-    const key = Object.keys(GameMapType).find((k) => GameMapType[k] === map);
+    const key = Object.keys(GameMapType).find(
+      (k) => GameMapType[k as keyof typeof GameMapType] === map,
+    );
     const fileName = key?.toLowerCase();
 
     const mapData = {
diff --git a/src/core/game/FetchGameMapLoader.ts b/src/core/game/FetchGameMapLoader.ts
index 5d6c72367..cfde1360f 100644
--- a/src/core/game/FetchGameMapLoader.ts
+++ b/src/core/game/FetchGameMapLoader.ts
@@ -17,7 +17,9 @@ export class FetchGameMapLoader implements GameMapLoader {
       return cachedMap;
     }
 
-    const key = Object.keys(GameMapType).find((k) => GameMapType[k] === map);
+    const key = Object.keys(GameMapType).find(
+      (k) => GameMapType[k as keyof typeof GameMapType] === map,
+    );
     const fileName = key?.toLowerCase();
 
     if (!fileName) {
diff --git a/src/core/game/Game.ts b/src/core/game/Game.ts
index 2a4991afd..6272d4622 100644
--- a/src/core/game/Game.ts
+++ b/src/core/game/Game.ts
@@ -9,6 +9,7 @@ import {
 } from "./GameUpdates";
 import { RailNetwork } from "./RailNetwork";
 import { Stats } from "./Stats";
+import { UnitPredicate } from "./UnitGrid";
 
 export type PlayerID = string;
 export type Tick = number;
@@ -389,9 +390,10 @@ export class PlayerInfo {
   }
 }
 
-export function isUnit(unit: Unit | UnitParams<UnitType>): unit is Unit {
+export function isUnit(unit: unknown): unit is Unit {
   return (
-    unit !== undefined &&
+    unit &&
+    typeof unit === "object" &&
     "isUnit" in unit &&
     typeof unit.isUnit === "function" &&
     unit.isUnit()
@@ -662,12 +664,12 @@ export interface Game extends GameMap {
     searchRange: number,
     type: UnitType,
     playerId: PlayerID,
-  );
+  ): boolean;
   nearbyUnits(
     tile: TileRef,
     searchRange: number,
     types: UnitType | UnitType[],
-    predicate?: (value: { unit: Unit; distSquared: number }) => boolean,
+    predicate?: UnitPredicate,
   ): Array<{ unit: Unit; distSquared: number }>;
 
   addExecution(...exec: Execution[]): void;
@@ -703,7 +705,7 @@ export interface Game extends GameMap {
 
   addUpdate(update: GameUpdate): void;
   railNetwork(): RailNetwork;
-  conquerPlayer(conqueror: Player, conquered: Player);
+  conquerPlayer(conqueror: Player, conquered: Player): void;
 }
 
 export interface PlayerActions {
diff --git a/src/core/game/GameImpl.ts b/src/core/game/GameImpl.ts
index 1d6349608..b85073e75 100644
--- a/src/core/game/GameImpl.ts
+++ b/src/core/game/GameImpl.ts
@@ -40,7 +40,7 @@ import { Stats } from "./Stats";
 import { StatsImpl } from "./StatsImpl";
 import { assignTeams } from "./TeamAssignment";
 import { TerraNulliusImpl } from "./TerraNulliusImpl";
-import { UnitGrid } from "./UnitGrid";
+import { UnitGrid, UnitPredicate } from "./UnitGrid";
 
 export function createGame(
   humans: PlayerInfo[],
@@ -758,7 +758,7 @@ export class GameImpl implements Game {
     tile: TileRef,
     searchRange: number,
     types: UnitType | UnitType[],
-    predicate?: (value: { unit: Unit; distSquared: number }) => boolean,
+    predicate?: UnitPredicate,
   ): Array<{ unit: Unit; distSquared: number }> {
     return this.unitGrid.nearbyUnits(
       tile,
diff --git a/src/core/game/GameUpdates.ts b/src/core/game/GameUpdates.ts
index 4dcf48149..c04eea8d8 100644
--- a/src/core/game/GameUpdates.ts
+++ b/src/core/game/GameUpdates.ts
@@ -18,7 +18,7 @@ export interface GameUpdateViewData {
   tick: number;
   updates: GameUpdates;
   packedTileUpdates: BigUint64Array;
-  playerNameViewData: Record<number, NameViewData>;
+  playerNameViewData: Record<string, NameViewData>;
 }
 
 export interface ErrorUpdate {
diff --git a/src/core/game/GameView.ts b/src/core/game/GameView.ts
index 70cbcbf52..12973a056 100644
--- a/src/core/game/GameView.ts
+++ b/src/core/game/GameView.ts
@@ -34,7 +34,7 @@ import {
 } from "./GameUpdates";
 import { TerrainMapData } from "./TerrainMapLoader";
 import { TerraNulliusImpl } from "./TerraNulliusImpl";
-import { UnitGrid } from "./UnitGrid";
+import { UnitGrid, UnitPredicate } from "./UnitGrid";
 import { UserSettings } from "./UserSettings";
 
 const userSettings: UserSettings = new UserSettings();
@@ -472,7 +472,7 @@ export class GameView implements GameMap {
     tile: TileRef,
     searchRange: number,
     types: UnitType | UnitType[],
-    predicate?: (value: { unit: UnitView; distSquared: number }) => boolean,
+    predicate?: UnitPredicate,
   ): Array<{ unit: UnitView; distSquared: number }> {
     return this.unitGrid.nearbyUnits(
       tile,
diff --git a/src/core/game/PlayerImpl.ts b/src/core/game/PlayerImpl.ts
index 59f2819ac..3fe210f59 100644
--- a/src/core/game/PlayerImpl.ts
+++ b/src/core/game/PlayerImpl.ts
@@ -211,9 +211,9 @@ export class PlayerImpl implements Player {
     return this._units.filter((u) => ts.has(u.type()));
   }
 
-  private numUnitsConstructed: number[] = [];
+  private numUnitsConstructed: Partial<Record<UnitType, number>> = {};
   private recordUnitConstructed(type: UnitType): void {
-    if (type in this.numUnitsConstructed) {
+    if (this.numUnitsConstructed[type] !== undefined) {
       this.numUnitsConstructed[type]++;
     } else {
       this.numUnitsConstructed[type] = 1;
diff --git a/src/core/game/UnitGrid.ts b/src/core/game/UnitGrid.ts
index 027f1b33f..15617c752 100644
--- a/src/core/game/UnitGrid.ts
+++ b/src/core/game/UnitGrid.ts
@@ -2,6 +2,11 @@ import { PlayerID, Unit, UnitType } from "./Game";
 import { GameMap, TileRef } from "./GameMap";
 import { UnitView } from "./GameView";
 
+export type UnitPredicate = (value: {
+  unit: Unit | UnitView;
+  distSquared: number;
+}) => boolean;
+
 export class UnitGrid {
   private grid: Map<UnitType, Set<Unit | UnitView>>[][];
   private readonly cellSize = 100;
@@ -130,11 +135,8 @@ export class UnitGrid {
   nearbyUnits(
     tile: TileRef,
     searchRange: number,
-    types: UnitType | UnitType[],
-    predicate?: (value: {
-      unit: Unit | UnitView;
-      distSquared: number;
-    }) => boolean,
+    types: readonly UnitType[] | UnitType,
+    predicate?: UnitPredicate,
   ): Array<{ unit: Unit | UnitView; distSquared: number }> {
     const nearby: Array<{ unit: Unit | UnitView; distSquared: number }> = [];
     const { startGridX, endGridX, startGridY, endGridY } = this.getCellsInRange(
diff --git a/src/core/utilities/Line.ts b/src/core/utilities/Line.ts
index e8c673533..67024e9c6 100644
--- a/src/core/utilities/Line.ts
+++ b/src/core/utilities/Line.ts
@@ -124,7 +124,7 @@ export class DistanceBasedBezierCurve extends CubicBezierCurve {
   /**
    * Precompute all points spaced @p pixelSpacing apart
    */
-  computeAllPoints(pixelSpacing: number, precision): void {
+  computeAllPoints(pixelSpacing: number, precision: number): void {
     this.cachedPoints = [];
     this.totalDistance = 0;
     this.currentIndex = 0;
diff --git a/src/core/worker/Worker.worker.ts b/src/core/worker/Worker.worker.ts
index 29e67f214..1014968fb 100644
--- a/src/core/worker/Worker.worker.ts
+++ b/src/core/worker/Worker.worker.ts
@@ -1,7 +1,7 @@
 import version from "../../../resources/version.txt";
 import { createGameRunner, GameRunner } from "../GameRunner";
 import { FetchGameMapLoader } from "../game/FetchGameMapLoader";
-import { GameUpdateViewData } from "../game/GameUpdates";
+import { ErrorUpdate, GameUpdateViewData } from "../game/GameUpdates";
 import {
   AttackAveragePositionResultMessage,
   InitializedMessage,
@@ -17,7 +17,11 @@ const ctx: Worker = self as any;
 let gameRunner: Promise<GameRunner> | null = null;
 const mapLoader = new FetchGameMapLoader(`/maps`, version);
 
-function gameUpdate(gu: GameUpdateViewData) {
+function gameUpdate(gu: GameUpdateViewData | ErrorUpdate) {
+  // skip if ErrorUpdate
+  if (!("updates" in gu)) {
+    return;
+  }
   sendMessage({
     type: "game_update",
     gameUpdate: gu,
diff --git a/tests/UnitGrid.test.ts b/tests/UnitGrid.test.ts
index 9a0869ace..bd6629910 100644
--- a/tests/UnitGrid.test.ts
+++ b/tests/UnitGrid.test.ts
@@ -29,7 +29,7 @@ async function nearbyUnits(
   unitPosX: number,
   rangeCheck: number,
   range: number,
-  unitTypes: UnitType[],
+  unitTypes: readonly UnitType[],
 ) {
   const game = await setup(mapName, { infiniteGold: true, instantBuild: true });
   const grid = new UnitGrid(game.map());
@@ -51,7 +51,7 @@ describe("Unit Grid range tests", () => {
     ["plains", 0, 10, 11, false], // Exactly 1px outside
     ["big_plains", 0, 198, 42, true], // Inside huge range
     ["big_plains", 0, 198, 199, false], // Exactly 1px outside huge range
-  ];
+  ] as const;
 
   describe("Is unit in range", () => {
     test.each(hasUnitCases)(
@@ -77,25 +77,18 @@ describe("Unit Grid range tests", () => {
     ["plains", 0, 10, 11, [UnitType.DefensePost], 0], // 1px outside
     ["big_plains", 0, 198, 42, [UnitType.TradeShip], 1], // Inside huge range
     ["big_plains", 0, 198, 199, [UnitType.TransportShip], 0], // 1px outside
-  ];
+  ] as const;
 
   describe("Retrieve all units in range", () => {
     test.each(unitsInRangeCases)(
       "on %p map, look if unit at position %p with a range of %p is in range of %p position, returns %p",
-      async (
-        mapName: string,
-        unitPosX: number,
-        range: number,
-        rangeCheck: number,
-        units: UnitType[],
-        expectedResult: number,
-      ) => {
+      async (mapName, unitPosX, range, rangeCheck, units, expectedResult) => {
         const result = await nearbyUnits(
           mapName,
           unitPosX,
           rangeCheck,
           range,
-          units,
+          units, // remove readonly
         );
         expect(result.length).toBe(expectedResult);
       },
diff --git a/tsconfig.json b/tsconfig.json
index 7c73290f3..6de45daab 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -21,7 +21,8 @@
     "resolveJsonModule": true,
     "strictNullChecks": true,
     "useDefineForClassFields": false,
-    "strictPropertyInitialization": false
+    "strictPropertyInitialization": false,
+    "strict": true
   },
   "include": [
     "src/**/*",