diff --git a/src/ts/Configs.ts b/src/ts/Configs.ts
index 51f84f1..c9db29b 100644
--- a/src/ts/Configs.ts
+++ b/src/ts/Configs.ts
@@ -42,8 +42,8 @@ export default class Configs
     public static set(name: string, value: scalar|scalar[]): Promise<void>
     {
         const getUpdatedArray = (path: string[], array: scalar|scalar[], value: scalar|scalar[]): scalar|scalar[] => {
-            array[path[0]] = path.length > 1 ?
-                getUpdatedArray(path.slice(1), array[path[0]] ?? {}, value) : value;
+            array![path[0]] = path.length > 1 ?
+                getUpdatedArray(path.slice(1), array![path[0]] ?? {}, value) : value;
 
             return array;
         };
@@ -74,14 +74,14 @@ export default class Configs
         return new Promise(async (resolve) => {
             const setDefaults = async (current: scalar) => {
                 const updateDefaults = (current: scalar, defaults: scalar) => {
-                    Object.keys(defaults).forEach((key) => {
+                    Object.keys(defaults!).forEach((key) => {
                         // If the field exists in defaults and doesn't exist in current
-                        if (current[key] === undefined)
-                            current[key] = defaults[key];
+                        if (current![key] === undefined)
+                            current![key] = defaults![key];
 
                         // If both of default and current are objects
-                        else if (typeof current[key] == 'object' && typeof defaults[key] == 'object')
-                            current[key] = updateDefaults(current[key], defaults[key]);
+                        else if (typeof current![key] == 'object' && typeof defaults![key] == 'object')
+                            current![key] = updateDefaults(current![key], defaults![key]);
                     });
 
                     return current;
diff --git a/src/ts/Game.ts b/src/ts/Game.ts
index e41f2e0..9bfb27c 100644
--- a/src/ts/Game.ts
+++ b/src/ts/Game.ts
@@ -6,6 +6,7 @@ import type {
 } from './types/GameData';
 
 import constants from './Constants';
+import fetch from './core/Fetch';
 
 declare const Neutralino;
 
@@ -48,7 +49,7 @@ export default class Game
 
             if (response.ok)
             {
-                const json: ServerResponse = await response.json();
+                const json: ServerResponse = await (response as any).json();
 
                 if (json.message == 'OK')
                     resolve(json.data);
diff --git a/src/ts/Voice.ts b/src/ts/Voice.ts
index 84e30eb..d830579 100644
--- a/src/ts/Voice.ts
+++ b/src/ts/Voice.ts
@@ -74,7 +74,7 @@ export default class Voice
     {
         return new Promise((resolve, reject) => {
             Game.getDiff(version)
-                .then((data) => resolve(data.voice_packs ?? null))
+                .then((data) => resolve(data!.voice_packs ?? null))
                 .catch((error) => reject(error));
         });
     }
diff --git a/src/ts/core/Archive.ts b/src/ts/core/Archive.ts
index 4e0d131..19481c1 100644
--- a/src/ts/core/Archive.ts
+++ b/src/ts/core/Archive.ts
@@ -19,7 +19,7 @@ class Stream
     protected unpackDir: string|null;
     protected unpacked: number = 0;
 
-    protected archive: ArchiveInfo;
+    protected archive?: ArchiveInfo;
 
     protected onStart?: () => void;
     protected onProgress?: (current: number, total: number, difference: number) => void;
@@ -59,7 +59,7 @@ class Stream
                 const command = {
                     tar: `tar -xvf "${path}"${unpackDir ? ` -C "${unpackDir}"` : ''}`,
                     zip: `unzip -o "${path}"${unpackDir ? ` -d "${unpackDir}"` : ''}`
-                }[this.archive.type];
+                }[this.archive.type!];
 
                 let remainedFiles = this.archive.files;
                 
@@ -77,8 +77,8 @@ class Stream
                         {
                             Neutralino.filesystem.getStats(`${baseDir}/${file.path}`)
                                 .then(() => {
-                                    this.unpacked += file.size.uncompressed;
-                                    difference += file.size.uncompressed;
+                                    this.unpacked += file.size.uncompressed!;
+                                    difference += file.size.uncompressed!;
 
                                     file.path = '#unpacked#';
                                 })
@@ -89,9 +89,9 @@ class Stream
                     remainedFiles = remainedFiles.filter((file) => file.path != '#unpacked#');
 
                     if (this.onProgress)
-                        this.onProgress(this.unpacked, this.archive.size.uncompressed, difference);
+                        this.onProgress(this.unpacked, this.archive!.size.uncompressed!, difference);
 
-                    if (this.unpacked >= this.archive.size.uncompressed)
+                    if (this.unpacked >= this.archive!.size.uncompressed!)
                     {
                         this.finished = true;
     
@@ -204,7 +204,7 @@ export default class Archive
                     {
                         let fileSize = parseInt(match[1]);
 
-                        archive.size.uncompressed += fileSize;
+                        archive.size.uncompressed! += fileSize;
 
                         archive.files.push({
                             path: match[2],
@@ -227,8 +227,8 @@ export default class Archive
                         let uncompressedSize = parseInt(match[1]),
                             compressedSize = parseInt(match[2]);
 
-                        archive.size.compressed   += compressedSize;
-                        archive.size.uncompressed += uncompressedSize;
+                        archive.size.compressed!   += compressedSize;
+                        archive.size.uncompressed! += uncompressedSize;
 
                         archive.files.push({
                             path: match[3],
diff --git a/src/ts/core/DXVK.ts b/src/ts/core/DXVK.ts
index c2c23aa..6053e3c 100644
--- a/src/ts/core/DXVK.ts
+++ b/src/ts/core/DXVK.ts
@@ -59,7 +59,7 @@ export default class DXVK
             // then we should find this DXVK version and call this method for it
             if (typeof dxvk == 'string')
             {
-                let foundDXVK = null;
+                let foundDXVK;
 
                 (await this.get()).forEach((currDxvk) => {
                     if (currDxvk.version == dxvk)
diff --git a/src/ts/core/Downloader.ts b/src/ts/core/Downloader.ts
index 6b70eed..d62c6ee 100644
--- a/src/ts/core/Downloader.ts
+++ b/src/ts/core/Downloader.ts
@@ -110,14 +110,14 @@ export default class Downloader
     {
         return new Promise(async (resolve) => {
             fetch(uri).then((response) => {
-                resolve(new Stream(uri, output ?? this.fileFromUri(uri), response.length));
+                resolve(new Stream(uri, output ?? this.fileFromUri(uri), response.length!));
             });
         });
     }
 
     public static fileFromUri(uri: string): string
     {
-        const file = uri.split('/').pop().split('#')[0].split('?')[0];
+        const file = uri.split('/').pop()!.split('#')[0].split('?')[0];
 
         if (file === '')
             return 'index.html';
@@ -125,7 +125,7 @@ export default class Downloader
         else if (`https://${file}` != uri && `http://${file}` != uri)
             return file;
 
-        else 'index.html';
+        else return 'index.html';
     }
 }
 
diff --git a/src/ts/core/Fetch.ts b/src/ts/core/Fetch.ts
index 52b6e65..dd5c1bb 100644
--- a/src/ts/core/Fetch.ts
+++ b/src/ts/core/Fetch.ts
@@ -29,7 +29,7 @@ class Response
         this.length = length;
 
         // https://developer.mozilla.org/en-US/docs/Web/API/Response/ok
-        this.ok = status >= 200 && status <= 299;
+        this.ok = status! >= 200 && status! <= 299;
     }
 
     /**
diff --git a/src/ts/core/Runners.ts b/src/ts/core/Runners.ts
index 12c8300..ab6d4a9 100644
--- a/src/ts/core/Runners.ts
+++ b/src/ts/core/Runners.ts
@@ -71,7 +71,7 @@ class Runners
             // then we should find this runner and call this method for it
             if (typeof runner == 'string')
             {
-                let foundRunner = null;
+                let foundRunner;
 
                 (await this.get()).forEach((family) => {
                     family.runners.forEach((familyRunner) => {
diff --git a/src/ts/types/Archive.d.ts b/src/ts/types/Archive.d.ts
index b0bd31f..414f045 100644
--- a/src/ts/types/Archive.d.ts
+++ b/src/ts/types/Archive.d.ts
@@ -1,10 +1,11 @@
 type ArchiveType =
     | 'tar'
-    | 'zip';
+    | 'zip'
+    | null;
 
 type Size = {
-    compressed?: number;
-    uncompressed?: number;
+    compressed?: number | null;
+    uncompressed?: number | null;
 };
 
 type File = {