Хорошо. Тогда есть еще Голдсорсовый Base Defence в стиме. https://store.steampowered.com/app/632730/Base_Defense/
Отбиваем толпы врагов на небольшой арене. Прокачиваемся, улучшаем стволы у торговца, есть магия.
Нашел полезный и полный коммент в стиме, который все объяснит.
Be warned because this is NOT your typical HL Mod, is not very casual friendly and it has it's system to learn.
In this mod, you have three classes to choose:

Rushing: The most weak of all of the three but very powerful
Religious: A very good supporting class with summoning Angels
Provident: Another very good supporting class that can help your team to survive with HP / Ammo drops

When you enter, you can start with different weapons, depending on your class. Every time you survive 10 waves, your perk / class saves.
In your HUD, you will notice you have HP (Duh), Mana, EXP for next level, and your current money. When you kill, restore barricades or kill the hardest alien In-game, you get money or a drop, which you can use to trade with allies, buy weapons, upgrade your inventory, items, etc
Another important thing, when you kill NPC's, there's chance you get Salvage you always get it when you killl or Souls, with those, you can upgrade your weapons with unique stats, which is something you WILL need, because those npcs will kick HARD in later waves!
About Exp, killing npcs gives you xp, or "getting lucky", with that xp. The xp / money you earn, depends on how much damage you do, not just killing You can choose how to level up you character:

Legerity: Speed / Gravity Reduction / Maximum ammo
Precision: Damage / Accuracy / Critical hit damage & chance
Toughness: Total HP / HP Regeneration / Damage Reduction
Sorcery: Total Mana / Mana regeneration
-Special Items can give extra efectiveness to some of above!

Playing multiplayer can be great fun, but check for your teammates and learn new stuff.
Playing Solo..WILL test how much knowledge & tactics you have (HL Itself and BDef) Enemies will deal a lot of damage and if you wanna fight IT, it will have a LOT of HP, and can end you VERY easily More easily at extremely higher waves! Take your time, Kite around, and it's worth it, because it can drop very valuable items to help you survive. And if you die..This is when Saves come in.
As I said before, every 10 waves, you save your progress (Stats, money and wave progress), but it's saved from the map by SteamID, NOT generally. You can choose which save to continue, which can be very helpfull if you want to know your class.
Currently achievements are being added, which is unusual to HL Mods
*A Difficulty selection (Easy = Softcore / Hard = Hardcore (Original difficulty)) has been added! So you should't die much now.

This mod isn't very hard for newcomers, but it will test you a lot AND punish you if it wants!.
Highly recommended for Half-Life Fans.
https://youtu.be/2N6ZR5NrMHc